AU744199B2 - High-definition television system - Google Patents

Description

1 A HIGH RESOLUTION TELEVISION SYSTEM FIELD OF THE INVENTION The invention relates generally to high-resolution television systems and more particularly to systems using at least two video cameras and devices for "stitching together" an integral image from parts. Such systems can be used primarily for the needs of roentgen functional diagnostics.

BACKGROUND OF THE INVENTION Systems used for roentgen functional diagnostics may be used for the following: for angiographic studies using x-ray contrast media, in particular for the determination of the patency of vessels and assessing the effectiveness of the blood supply of organs and tissues; for the roentgenoscopic monitoring of the course of surgical operations using probes, catheters, etc., instruments introduced into the organism through 15 the esophagus, anus, or blood vessels; S: for the roentgenoscopy of the lungs, heart, stomach, and other motile organs; for the roentgenography in traumatology; ooeeo for filmless fluorography in mass screening examinations of the public; and 20 for roengenography in urology and other fields in which the periodic Sobservation of the slow spread of x-ray contrast media in the organism is required.

••oo• Evaluations of the types indicated are becoming ever more large-scale and, in the aggregate, ever more expensive as medicine develops. Therefore, the rejection of the still and cinematic photography using film (and especially x-ray sensitive film) materials that were customary even recently has now been a serious problem for quite a long time.

It is natural that at the contemporary level of development of television and computer technology the shift to "filmless" roentgen diagnostics has been possible mainly through the creation of x-ray television systems.

However, there are several fundamental difficulties along this path.

The first of these is dictated by the fact that many physiological processes (especially circulatory) unfold at such a speed that x-ray contrast agents introduced into the vascular bed leave the zone of observation in roughly several seconds. Therefore, the objective need exists for quite high-speed (at a frame rate no less than 25 frames per second) video filming.

Further, the diagnostic value of x-ray television images depends to a substantial degree on their resolution. In other words, their spatial resolution (from 3 to 5 line-pairs per mm) and contrast must be no poorer than for images on film.

Correspondingly, decomposition of the integral image into no fewer than 3000x4000 pixels should be acceptable.

And, finally, x-ray television systems must be as simple and, accordingly, technologically feasible to manufacture, affordable, dependable, and convenient to operate.

The separate fulfillment of these requirements through the construction of television systems using special television cameras does not present significant difficulties.

In fact, the KAF-1 6800 model (Kodak) television camera (abbreviated, video camera), based on MOS (metal oxide semiconductor) structures, and also including MOS transistors in the output stages, with a format of 4096x4096 pixels, is known (News Briefs, Tech Briefs... Medical Imaging, The Business Magazine for Technlogy Management, Vol. 10, No. 12, 1995, p. This video camera, according to available data, is unique in its resolution.

However, due to the necessity of aberration correction, it has a highly complex construction (especially the optics), and is therefore expensive to manufacture and operate. in addition, the MOS structures provide a frame rate no greater than than 0.5 frames per second; this is acceptable, for example, for filmless roentgenography in traumnatology, but substantially lower than the required minimum of 25 frames per second for angiography and even for the monitoring of the course of surgical procedures (about 7 frames per second).

Therefore, attempts to increase the resolution and frame rate in x-ray television systems using substantially less expensive and high-reliability traditional video cameras.

Thus, a television system with 2000 line scan and resolution no greater than 1350 pixels per line has been built based on a Philips SXQ5002 tube (Murphy Bitler Lybrook Slevener T., v~Tre..cm Broemelsiek M. The application of a Plumbicon TV-Camera Tube in 2000-Line System. Proc. SPIE. 1994, Vol. 2163, p. 333-339).

Due to the limited 20 MHz frequency band of the video signal, this system has a frame rate no greater than than 7.5 frames per second. Such a frame rate is sufficient, for example, for roentgenoscopic monitoring of the course of surgical procedures, but is clearly inadequate for angiographic examinations. Standard calculations for specialists in this art have shown that broadening the frequency band of the video signal up to 30 MHz could achieve a resolution up to 2000 pixels per line, but at the same frame rate of frames per second. However, this broadenin is made difficult by the necessity of creating a specialized video preamplifier using broad-band input stages, and by the necessity of decreasing the intrinsic noise level of the image tube.

An increase in resolution up to 2000 x 2000 pixels in one frame is achieved in the x-ray television system for gastrointestinal examinations through the use of SATICON video cameras which are connected optically to the x-ray source through an optical splitter and an x-ray optoelectronic transducer (Ogura N., Masuda Fujita H. Technical and Clinical Evaluations of a 2048x2048 Matrix Digital Radiography System for Gastrointestinal Examinations. Ibid. 1991, Vol. 1443, p. 401-408). This made it possible to obtain a frame rate of just 0.94 frames per second.

To avoid broadening of the frequency band of the video signal by overcoming the above-mentioned difficulties, it is advisable to use such a television system only for the observation of slowly unfolding physiological processes, while fast processes may be filmed on wide (up to 1 00 mm) movie film for later analysis.

These devices are convenient (even if expensive) for diagnostic examinations in situations in which the life of the patient is not in immediate danger, but are not practically applicable for the roentgenoscopic monitoring of the course of surgical procedures and are ill-suited for large-scale fluorographic screening of the population.

Attempts to use high-resolution video cameras based on largeformat charge-coupled semiconductor devices (from here on, abbreviated CCD) described by Z. Ninkov, et al. (Characterization of a Large-Format CCD Array. Optical engineering, 1995, Vol. 34, No. 1) in x-ray television systems with a frame rate no less than than frames per second are associated with even higher requirements for the frequency band width of the video signals.

~4~-U~t2~ 4 Thus, the frequency band of the video signals for commercially available video cameras based on CCD arrays does not exceed 30 MHz.

However, the frequency band width of the video signal must be about 100 MHz even for the decomposition of images into 2000x2000 pixels at a frame rate of 25 frames per second. When shifting to a format of 3000x4000 pixels, which is close to the resolution of 30x40 cm x-ray film, the frequency band width of the video signal must now be about 300 MHz; this exceeds the capacity of existing video cameras based on CCD arrays many-fold.

A natural way out of these difficulties may be achieved by creating multicamera television systems, in which each of the highspeed video cameras with a standard frequency band of the video signal is aimed at part of the object under examination or observation, and the set of images obtained can be used to represent such an object as a whole.

Television security and surveillance systems, for example, VC-Profi (V701-003), CSS-4223, and Videoman (JHV-501), in which at least two video cameras are connected to a a common monitor and/or a composite image analyzer (see the catalog, "Equipment for Television Observation and Television Monitoring Systems", Ultra Star, South Korea, published by the Center for Security Technologies in Moscow, 1995, p. 36), may serve as the simplest example of the use of this principle.

Such systems are entirely effective for the discrimination of moving or low-contrast objects in a general field of observation.

However, the composite image formed by them consists of individual parts clearly corresponding to the fields of view of the individual video cameras, with clearly visble boundaries between such parts, and the resolution of such systems is equal in essence to the resolution of the monitor on which the composite image is displayed.

Therefore, these systems cannot be used without substantial improvements as components of systems of observation of integral objects (requiring detailed imaging), and especially as components of x-ray diagnostic systems for the needs of angiography (as well as for monitoring the course of surgical procedures).

Nevertheless, systems of this type can serve as the basis for the creation of high-resolution x-ray television systems.

It may be assumed that with respect to technical essence, a high-resolution television system (in the original "Multi-source Image Real Time Mixing and Anti-Aliasing") according to USA patent 5,351,067 (Lumelsky L. et al) is the closest such system to the proposed system.

That system has: at least two input source channels for parts of the required image, in particular, at least two video cameras; connected in series to each of said channels: analog-to-dligital converters (from here on, ADCs); internal memory (from here on, RAM); and input video standards converters; devices for synthesis of the video output signal connected to the outputs of the video cameras and comprising: at least two mixers that are connected to the outputs of these standards converters; at least two multiplexers, in which: the control inputs are connected to a common control unit containing a personal computer buffer memory module, and a video splitter, said mixers are connected to the first data inputs and said standards converters are connected to the second data inputs, and which, starting from the second, are connected in series through the third data inputs to the preceding multiplexers, while a high-resolution monitor (display) is connected to the output of the last multiplexer; a central processor based on a PC.

A substantial (up to 260 MHz) broadening of the common frequency band of the video output signal is achieved in the described television system by means of the multiplexers, and the objective is thereby achieved of the visualization simultaneously on the same screen of several images, whose position can be selected as the operator wishes in various combinations and scales, and which can replace one another at a frequency of 25 frames per second and higher.

However, even when the input video cameras are placed so that the aggregate of their fields of view covers the entire area of any integral object under observation or examination, it is not possible to form an integral image at the output of the system without visible boundaries of the fields of view of the individual video cameras. This undesirable effect arises: first, because geometric distortions are unavoidable (even if each is individually neglible) in each input stage, which will be all the more noticeable in the output (synthesized) video signal, the 6 closer the objectives of the video cameras are to the object under observation or examination; second, especially because the apparatus used to obtain the initial data (video cameras, AD~s, etc.) cannot be absolutely identical in their operating characteristics.

.As a result, the systems described cannot be used effectively as a component of systems for observation of integral (requiring detailed imaging) objects, and especially as components of high-resolution diagnostic x-ray television systems for the analysis of moving images, in which. the distance between the objectives of the video cameras and the object under examination (for example, the circulatory system) or observation) for example, a surgical probe, advances along a tubular organ) must be as short as possible. The need for the minimization of said distance is determined.

:First, by the need to decrease radiation exposure of the human organism (and this exposure can be attenuated by maximally utilizing the luminous flux at the output of the primary transducer converting x-radiation to visible light); second, by the need to obtain the most detailed images possible of the objects under examination or observation.

Any discussion of documents, devices, acts or knowledge in this specification is 20 included to explain the context of the invention. It should not be taken as an admission that any of the material formed part of the prior art base or the common general knowledge in the relevant art in Australia on or before the priority date of the claims herein.

*The present invention is directed towards alleviating at least one of the problems of the prior art.

SUMMARY OF THE INVENTION In one aspect, the present invention provides a high-resolution television system having at least two video cameras, analog-to-digital converters (ADCs), a video standards converter, internal memory (RAM), means for synthesizing the video output signal connected to the outputs of the video cameras and interconnected, and a central processor wherein the video output synthesizes include a multichannel geometric distortion corrector and a synchronizer; said orrector is at the same time connected through the ADO to the outputs of the video cameras and through the video standards converter and RAM to the input of the control processor, while the synchronizer is connected through its control input to the synchronization output of at least one of the video cameras, and through its control outputs to the clock input of the ADC, to the address inputs of the video standards converter.

Preferably, the television system is equipped with a source of primary (xray) radiation and a converter of the x-ray image to a visual image which are mounted in front of the video cameras. In the majority of cases, this addition is sufficient for the use of the proposed television system as a component of x-ray diagnostic systems.

Additionally, the television system may be equipped with at least one calibration test object in the form of a three-dimensional target which can be placed in front of the video cameras when the system is being adjusted. The :a adjustment of the proposed television system for the "stitching" of individual 15 images of parts of an object to be examined or observed into an integral image of this object is thus facilitated.

The television system may also be equipped with a means for placing test objects in the field of view and removing these test objects from the field of view Sof the video cameras, which is connected to the control synchronizing output of 20 the synchronizer while this synchronizer is additionally interconnected with the o central processor by a feedback-control loop. The automatic adjustment of the television system when the necessity exists for online correction of the quality of S the "stitching" of the integral image from the images of the individual video cameras is thus achieved.

Preferably, the television system is equipped with a high-resolution monitor which is connected to the data output of the video standards converter and RAM.

The possibility is thereby secured of the direct perception by the operator of the "stitched" integral image of the object under observation of examination (at a frequency no less than 25 frames per second).

In one embodiment of the invention, the multichannel geometric distortion corrector has, in each of the channels of the television system: Zat the input: 1 111-11111 11-1 1 1_1 _11_11_1 8 -at least two identical calculation circuits for generating the corrected coordinates along the horizontal and the vertical, respectively, of each of the pixels in the video output signal, computed on the basis of the initial coordinates of analogous elements of the image in the video input signal and correction factors; -at least two identical slave memory modules for the digital video input signal, connected to said calculation circuits as the sources of the addresses for readout of data on the corrected pixels of the video output signal, while -at the output: -an inverter, which is inserted between the above-indicated synchronizer and one of said slave. memory modules, and -an output multiplex for the alternate connection of the outputs of said :slave memory modules to the input of the above-mentioned video standards converters and RAM.

Such a structure of the multichannel geometric distortion corrector is preferable for x-ray television systems adjusted for the "stitching together" the integral image from images formed by individual video cameras, using rigid threedimensional targets.

Preferably, in the multichannel corrector: each of said calculation circuits has at least: one input comparator with fixed threshold digital code, connected to the output of one of the ADCs, OF C-C IC VCttsr C4,}CkCCS~YC s- 8a -one decoder, connected to the address outputs for the pixel coordinates of the input image of the above-mentioned synchronizer, and having two control inputs, 11 two AND logic circuits, each of which is connected to the output of said comparator and to the control output- of the synchronizer, and one of which is connected to the first and the other to the second control output of said decoder, -two nonvolatile RAMs, in which: -the control inputs are independently connected to the outputs of the respective AND circuits and address and data inputs are also independently connected respectively to the address inputs of the above-mentioned synchronizer; one decoder, connected to the address output of one of the coordinates of each of the pixels of the input image from the abovementioned synchronizer (in the process, the signal corresponding to one of the coordinates of each of the pixels of the input image is sent to the data inputs of the first and second nonvolatile RAMs of the first calculation circuit; the signal corresponding to the second coordinate of each of the pixels of the input image arrives at the address inputs of the same RAMs, while said signals are sent in reverse order to the corresponding inputs of the first and second nonvolatile RAMs and to the decoder of the second calculation circuit), one differential stage with two data inputs separately connected respectively to the data outputs of said nonvolatile RAMs, a normalizer for integer division of the digital parallel code of the signal setting one coordinate of each pixel of the distorted image, by the digital code of a constant setting one of the geometric dimensions of the undistorted raster (respectively along the horizontal in one calculation circuit and along the vertical in the other calculation circuit), a multiplier for multiplication of the digital codes of one of the normalized coordinates of each of the pixels of the input image by the digital code of the active dimension of the distorted raster corresponding to this coordinate, an adder for adding the digital codes of the coordinates of the origin of the representation of the distorted field of the image and the current increment in the coordinate of the processed pixel of the image in the same raster, while each slave memory module has: two input multiplexers, each of which is designed for generation of the corresponding digital codes of the coordinates of an*~?xp~ the pixels of the input and corrected image, and connected to said multiplexes RAM for writing the video input signal to one address and reading the video signal of the corrected image output from the other address.

The described structure of the channels of the geometric distortion corrector most effectively facilitates the "stitching" of the integral image from the fragmentary images formed by the individual video cameras, with effectively complete exclusion of information loss at the seams.

In a preferred embodiment, the video standards converter is combined with said RAM and has: RAM banks with isolated data inputs, the number of which bank is equal to the number of video cameras, and to each of which the following are connected: -two address multiplexes and -two frame buffers; a control decoder for the RAM banks; 15 a first digital-to-analog converter; buffer RAM, containing: memory modules connected in parallel, the number of which is equal to the number of video cameras, and a buffer RAM decoder and 20 a second digital-to-analog converter.

The combination of the video standards converter with RAM reduces the C instrumentation required to perform said functions as applied to television and especially x-ray television systems orientated toward the "stitching" of the integral image from the images formed by the individual video cameras.

Preferably in the combined video standards converter with RAM there are: in each RAM bank: the data inputs of the frame buffers are combined and connected to the corresponding outputs of said multichannel geometric distortion corrector, and their data outputs are also combined (including between banks) and connected to the data input of the first digital-to-analog converter; the first inputs of the multiplexers are combined and connected to the synchronizing outputs for the codes of the coordinates for writing the corrected images into the frame buffers in the above-mentioned synchronizer, while the second inputs of the

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multiplexers are also combined and connected to the synchronizing outputs for the codes of the coordinates for reading the corrected images from the frame buffers in the above-mentioned synchronizer; the first outputs of the first multiplexer are connected to the corresponding address inputs of the first frame buffer, while the first outputs of the second multiplexer are connected to the corresponding address inputs of the second frame buffer; the second control input of the first multiplexer and the second inverted control input of the second multiplexer are connected to the control output of the above-mentioned synchronizer; the first outputs of the multiplexers are connected to the address inputs, their second outputs are connected to the chipselect control inputs, and their third outputs are connected to the read-write control inputs of the corresponding RAMs; in all RAM banks: the first control inputs of the first and second multiplexers are combined and connected respectively to the first, second, etc.

outputs of the decoder, while the data outputs of all frame buffers are combined and connected to the data input of the first digital-to-analog converter; the control input of the decoder is connected to the control output of the above-mentioned synchronizer; the first and second control inputs of the first digital-toanalog converter are connected respectively to the synchronizing outputs of the above-mentioned synchronizer, while the data output of this converter is connected to the above-mentioned highresolution monitor; the address inputs of the buffer RAM memory modules are combined and connected to the synchronizing outputs of the abovementioned synchronizer with the codes of the coordinates; their data inputs are connected to the corresponding outputs of the abovementioned multichannel geometric distortion corrector; their data outputs are combined and connected to the data input of the second digital-to-analog converter; their read-write control inputs are connected to the control output of the above-mentioned synchronizer, while the data input of the last memory module of said buffer RAM is connected to the corresponding data input of the frame buffer; the control inputs of the buffer RAM decoder are connected \to the corresponding control outputs of the above-mentioned synchronizer, while the control outputs of said decoder are connected to the chip select inputs of the memory modules so that the first of said outputs is connected with said input of the first memory module, the second with the input of the second memory module, etc; the data input of the second digital-to-analog converter is connected to the combined data outputs of the memory modules; the control inputs of this converter are connected to respectively the synchronizing outputs of said synchronizer, while its data output is connected to the above-mentioned module for inputting the video signals to the PC.

The specific structure described of the combination video standards converter with RAM is preferable for the formation of an integral large-format high-resolution image form many (10 and above) constituent parts, each of which is separately characterized by substantially lower resolution.

The ninth additional distinction consists in the fact that the synchronizer has: the first driving generator of synchronizing signals corresponding to the resolution standard of the video cameras, whose clock output is connected to the clock inputs of the abovementioned ADC modules and the multichannel threshold controller, and at least one second driving generator of synchronizing signals, corresponding to the high-resolution standard for the synthesized image; two groups of counters respectively for the X and Y coordinates of the pixels of the images formed by each of the video cameras, and two groups of counters respectively for the Xm and Ym coordinates of the pixels of the synthesized high-resolution image; at least one sync pulse selector designed to select the original synchronizing pulses from the total television signal and to form output horizontal and vertical synchronizing pulses; two digital comparators respectively for the codes of the Xm and Ym coordinates; two monostable multivibrators for the formation of horizontal (line) and vertical (frame) pulses corresponding to the highresolution standard; at least one counter to count the number of pixels in the synthesized high-resolution image; an AND circuit for conjunction in the process of formation of control signals for the above-mentioned geometric distortion corrector; an input register for receiving the control commands by said synchronizer sent from said PC; an output register for sending information about the state of said synchronizer to said PC, and an address decoder for the programmable port of said computer for outputting the control commands to said synchronizer, in which case: the first driving generator is connected to the count input of the first group of X coordinate counters; the count input of the second group of Y coordinate counters is connected to the output of the horizontal synchronizing pulses of the sync pulse selector; the first group of Xm coordinate counters is connected through the count input to the output of the second 'driving generator of synchronizing signals; the count input of the second group of Ym coordinate counters is connected to the output of the Xm coordinate counters through one of the digital comparators and one of the monostable multivibrators, connected in series; the reset inputs of the first group of X coordinate counters and of the first group of Xm coordinate counters are connected to the output of the horizontal synchronizing pulses of the sync pulse selector; the reset input. of the second group of Y coordinate counters is connected to that output of the sync pulse selector from which the vertical synchronizing pulses corresponding to the full frame of the output image of the video cameras must be taken; the reset input of the second group of Ym coordinate counters is connected to that output of the sync pulse selector from which the vertical synchronizing pulses corresponding to the half-frame of the output image of the video cameras must be taken; the output of the first group of Xm coordinate counters is connected: to the inputs of all the multiplexers and to the input of the memory bank control decoder of the above-mentioned video standards converter with RAM, and ~A32.~r~ ~r through the first digital comparator and the first monostable multivibrator, connected in series, to the digital-to-analog converter of the same converter with RAM, and also to the count input of the second group of Ym coordinate counters; the output of the second group of Ym coordinate counters is connected: to the inputs of all the multiplexers of the above-mentioned video standards converter with RAM, and through the second digital comparator and the second monostable multivibrator, connected in series, to the digital-toanalog converter of the same converter with RAM, and also to the count input of the counter of the number of pixels of the synthesized high-resolution image; the input register is connected: through a parallel data input to the computer, through the first output to the reset input of the counter of the number of pixels of the synthesized high-resolution image and to the control input of the video standards converter with RAM, through the second output to the second input of the AND circuit; through the third output to the reset input of the D flip-flop; the output register is connected: through the first input to the output of the vertical synchronizing pulses of the above-mentioned sync pulse selector, through the second input to the output of the counter of the number of pixels of the synthesized high-resolution image, and through the output to the PC; the address decoder of the programmable port of said PC for outputting control commands to the above-mentioned synchronizer is connected: through the input to the address bus of the PC, and through the output to the input of the input register; the counter of the number of pixels of the synthesized highresolution image is additionally connected to the control input of the buffer RAM decoder of the above-mentioned video standards converter with RAM.

Despite the seeming abundance of functional modules, the described construction of the synchronizer represents the simplest embodiment of the inventive conception for the needs of the proposed high-resolution x-ray television system.

~ha~- Preferably, the synchronizer is additionally equipped with a second AND circuit and D flip-flop, and: said AND circuit is connected through one input to the output of the driving generator of synchronizing signals corresponding to the resolution standard of the video cameras, through a second input to the inverted output of the D flip-flop, while the output may be used in a supplementary circuit for generation of input signals for the above-mentioned geometric distortion corrector, while said D flip-flop is connected: through the data input to the control output of the above-mentioned multichannel threshold controller, through the synchronizing output to the output of the selector of sync pulses corresponding to a full frame of the input image, through the reset input to the third output of the above-mentioned input register.

15 These additions facilitate enhancement of the quality of the operation of the geometric distortion corrector and, accordingly, the quality of the output image.

The television system of the present invention may also be equipped with a digital video signal amplitude corrector which is connected to the input of the 20 multichannel geometric distortion corrector, with interframe digital video signal accumulators, whose number is usually equal to the number of video cameras S and which are inserted between the ADC and said digital video signal amplitude S corrector, and with a multichannel threshold controller, which is connected to the S outputs of the digital video signal amplitude corrector, is connected through the above-mentioned synchronizer to the control inputs of the interframe digital video signal accumulators, and is equipped with a feedback control output in a feedback loop with the source of primary (x-ray) radiation.

A more complex high-resolution television system of this kind is preferable for the needs of x-ray diagnostics. In this respect, the digital video signal amplitude corrector is preferably multichannel, and has in each channel: 1 two nonvolatile RAMs, which are respectively intended for storage of the codes for the correction factors of the "black' level and maximum excursion of the video signal for each pixel of the S 't~P V yV~\ 16 input image from the video camera corresponding to the given channel; a differential stage for calculating the difference between the codes of the input signal and the "black" level for each pixel of the input image from the corresponding video camera; a divider for calculating the normalized amplitude correction factors for the video input signals by dividing the constant setting the code for the maximum excursion of the video signal for the selected video cameras and ADCs by the varying code corresponding to the maximum excursion of the video signal for each active pixel of the image input from the corresponding video camera; an address decoder for the programmable port of the PC for sending control commands to the given channel of the digital video signal amplitude corrector, in which the input is connected to the address bus of the PC; an input register to receive control commands coming from the PC, in which: the first input is connected to the PC data bus, the second input to the output of the address decoder, while the outputs are connected to the control inputs of the nonvolatile RAMs; an output multiplier for generation of codes for the normalized video output by multiplication of the aforementioned normalized factors times the code of the aforementioned difference signal), and: the first RAM is connected: through the data input to the output of the corresponding channel of the above-mentioned ADC module, through the control input to the first output of the input register, the second RAM is connected: through the data input to the output of said differential stage, through the control input to the second output of the input register, while both RAMs are connected through the address inputs to the X, Y output of the above-mentioned synchronizer; the differential stage is connected: through the first input to the output of the corresponding RAL channel of the above-mentioned ADC module, S,2f _g I C. 1 17 through the second input to the output of the first RAM, through the output to the first input of said multiplier; the divider is connected between the output of the second RAM and the second input of the multiplier.

The described structure of the digital video signal amplitude corrector is preferable for high-resolution roentgenoscopic television systems which, in the context of the limitations of the permissible absorbed doses, must consistently operate at x-ray power densities which are as low as possible. The use of such correctors in systems used to monitor the course of surgical procedures is especially important.

The thirteenth additional distinction consists in the fact that the multichannel threshold controller has: in each channel: a first comparator for comparing the codes of the pixels of the image formed by the video camera corresponding to the given channel, with the code of the threshold, an AND circuit, which through the first input is connected to the output of the comparator and is designed for strobing the clock signal with the output signal of this comparator, a counter, the count input of which is connected to the output of said AND circuit, and which serves to calculate the number of such pixels, in the image frame corresponding to the video camera connected to the given channel, whose code exceeds the preset threshold luminance value, a register, the data input of which is connected to the output of the counter and which serves to store the parallel output code of this counter, a second comparator whose input is connected through said register to the output of said counter and which serves to compare the output code of this counter with the preset threshold number of pixels of the image that have a luminance no less than the aforementioned threshold value, and a trigger, in which the data input is combined with the output of said comparator and which serves to write the logical output signal of this comparator at the end of the frame synchronization pulse from the above-mentioned synchronizer; and the following, in common for all channels: an address decoder for the programmable port of the PC for I outputting to the multichannel threshold controller the codes of the luminance threshold values, of the number of pixels with a luminance no less than the threshold value, and of the number of channels with logic level at the outputs, in which the input is connected to the address bus of the PC, an input register for receiving the codes of said threshold values arriving from the PC, in which the first (data) input is connected to the PC data bus, while the second (clock) input is connected to the output of the address decoder, the first output (of the code of the luminance threshold value) is connected to the combined first inputs of the first comparators of all channels, while the second output (of the number of pixels with a luminance no less than the preset value) is connected to the combined second inputs of the second comparators of all channels, a multiplexer for the multiplexing the output signals of all channels, in which each of the data inputs is connected to the outputs of the triggers of the corresponding channels, while the control input is connected to the synchronizing output of the abovementioned synchronizer with the X coordinate code; an AND circuit for strobing the clock signal with the output signal of said multiplexer, in which the first input is connected to the output of the multiplexer, while the second input is connected to the combined second inputs of said AND circuits of each of the channels of the multichannel threshhold controller and is connected to the clock output of the above-mentioned synchronizer; a counter for counting the number of those channels whose signals at the outputs of the triggers have logic level "1 and which is connected through the count input to the output of said AND circuit, while it is connected through the reset input across the inverter to the output of the frame synchronization pulses of the above-mentioned synchronizer; a comparator for comparing the output code of the counter with the threshold value of the number of channels with logic level at the outputs, connected through the first and second data inputs respectively to the output of the counter and the third output of said input register, while it is connected through the output to the controller of the primary (x-ray) radiation source, a trigger for writing and storing the output signal of said comparator, connected through the data input to the output of said comparator, through the clock input across said inverter to the frame synchronization pulse output of the above-mentioned synchronizer, and connected through the control output to the above- LJI1

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19 mentioned interframe digital video signal accumulators across the above-mentioned synchronizer; in which case: in each of the channels, the following are combined and jointly connected to the output of the frame synchronization pulses of the above-mentioned synchronizer: the reset inputs of the counters of the number of pixels with a luminance no less than the preset value, the clock inputs of all registers and the clock inputs of all triggers, while the second inputs of the first comparators of all channels are connected to the corresponding data outputs of the abovementioned digital video signal amplitude corrector.

The proposed construction of the multichannel threshhold controller makes it possible, when using the proposed x-ray television system for mass roentgenographic screenings, first, to regulate effectively the operation of the primary x-ray source in accordance with the criteria of permissible absorbed dose and of the required quality of the synthesized integral image, and second, to optimize the operation of the interframe accumulators.

Brief description of diacirams The essence of the invention is further explained by a detailed description of the proposed device with references to the appended diagrams, where the following are depicted on: fig. 1 block diagram of the proposed high-resolution television system in the simplest form of the hardware realization of the inventive conception; fig. 2 block diagram of the proposed high-resolution television system in the improved form of the hardware realization of the inventive conception; fig. 3 functional block diagram of the multichannel geometric distortion corrector; fig. 4 -functional block diagram of the standards converter with internal memory (RAM); fig. 5 -functional block diagram of the synchronizer; fig. 6 functional block diagram of one channel of the multichannel video signal amplitude corrector from fig. 2; fig. 7 functional block diagram of one channel of the N4, nterframe accumulator from fig. 2; "S ~t N a~aNaN~~' j- V 1 9a mentioned interframe digital video signal accumulators across the abovementioned synchronizer; in which case: in each of the channels, the following are combined and jointly connected to the output of the frame synchronization pulses of the abovementioned synchronizer: the reset inputs of the counters of the number of pixels with a luminance no less than the preset value, the clock inputs of all registers and the clock inputs of all triggers, while the second input of the first comparators of all channels are connected to the corresponding data outputs of the above-mentioned digital video signal amplitude corrector.

The proposed construction of the multichannel threshold controller makes it possible, when using the proposed x-ray television system for mass roentgenographic screenings, first, to regulate effectively the operation of the primary x-ray source in accordance with the criteria of permissible absorbed dose and of the required quality of the synthesized integral image, and second, to optimize the operation of the interframe accumulators.

"Comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not 0 preclude the presence or addition of one or more other features, integers, steps, components or groups thereof 0 BRIEF DESCRIPTION OF DRAWINGS The invention is further explained by a detailed description of the invention with reference to the accompanying drawings, in which: Figure 1 is a block diagram of the proposed high-resolution television system in the simplest form of the hardware realization of the inyentive conception; Figure 2 is a block diagram of the proposed high-resolution television system in the improved form of the hardware realization of the inventive conception; Figure 3 is a functional block diagram of the multichannel geometric distortion corrector; Figure 4 is a functional block diagram of the standards converter with internal memory (RAM); Figure 5 is a functional block diagram of the synchronizer; Figure 6 is a functional block diagram of one channel of the multichannel video signal amplitude corrector of Figure 2; Figure 7. is a functional block diagram of one channel of the interframe accumulator of Figure 2; Figure 8 is a functional block diagram of the multichannel threshold controller of Figure 2; Figure 9 is a schematic of test-object with vertical disposition of the threedimensional target; and :Figure 10 is a schematic of test-object with horizontal disposition of the three-dimensional target.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to an embodiment, the high-resolution television system, (see Figure has: at least two video cameras 1, which: are conjointly aligned so that their fields of view overlap negligibly (these cameras can be placed in horizontal and/or vertical rows, or when necessary, along the diagonal of an arbitrary rectangular profile) and are typically interconnected electrically by an external vertical and horizontal sweep synchronization circuit, operating for the output of one of the video cameras; a module 2 of analog-to-digital converters (from here on, ADCs), the number of which is equal to the number of video cameras 1 electrically connected to their inputs, and each of which ADO has a clock input, not specially designated; a multichannel geometric distortion corrector 3, which has (not specially designated, as will be the case from her on in similar instances, since this is obvious to the specialists in electronics): s 7 signal inputs, connected to the outputs of ADC module 2, a control input for transferring addresses, clock pulses, and commands; outputs of corrected digital video signals; a standards converter 4 for the video image, combined with internal memory (RAM), based, for example, on static memory (in particular, of the SRAM 128kx8 type, in the form of the commercially available TOSHIBA TC558128AJ microcircuits), which: is electrically connected to the signal inputs of said corrector 3, has a control input for the transmission of addresses, clock pulses, and commands and 6* o

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55

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a.ooo o *oo i- F +r ~i i4 4 4 21 is equipped with at least one data output, and preferably two data outputs for the transmission of corrected digital video signals to users; video input module 5 for inputting the video signals (again in digital form) into the computer (preferably a personal computer), which is electrically connected to one of the data outputs of said converter 4 and has at least one "data input-data output" pair; a high-speed PC 6 which is electrically connected to said module 5 by direct coupling and feedback across said "data inputdata output" pair; a synchronizer 7, which has: a synchronizing control input, electrically connected to the last of the video cameras 1 to receive the vertical and horizontal sweep sync signals, synchronizing control outputs to the clock inputs of each of the ADCs.in module 2, input/output for the data feedback from said PC 6; control and synchronizing outputs to the address inputs of said multichannel corrector 3, control and synchronizing outputs to said video image standards converter 4 and RAM, and a control and synchronizing output to said, and from here on designated, device for facilitating adjustment of the system.

A high-resolution monitor 8 may be connected to a second, additional output of said video image standards converter 4 for the direct demonstration of the television (in particular, x-ray television) image to the user of the visual information.

The video cameras 1 may be both conventional (for example, based on the VIDICON-type image tubes) and based (which is preferable) on CCD arrays, in particular of the Mintron Enterprises (USA) MTV-1802 type, or the Tektonix (USA) TK 2048 type with 2048x2048 pixels with buried channel, three-phase control, and a dynamic range of 80 dB (such an array measures 55.3x55.3 mm and the pixel size is 27x27 pm).

Video cameras of the first two of these types are preferable for high-speed x-ray television systems with a frame rate no less than 25 frames per second. Video cameras of the third type are preferable for high-resolution television systems for the processing of large-format initial images with a minimal number of "seams" of individual parts into the integral final image (for example, the archiving of aerial or space photographs, in which frame rate is not a critical parameter).

Any suitable, commercially available microcircuits can be used as the ADCs in module 2, for example, of the Analog Device, USA, AD876 type; the use of a multichannel ADC with electrically isolated channels according to the number of video cameras 1, is also possible.

The multichannel geometric distortion corrector 3 is described below in detail, with references to fig. 3.

The video image standards converter 4 with RAM may be constructed on the basis of a multichannel RAM, decoder, and multiplexers, as is described below in detail, with references to fig.

4.

Module 5 for inputting the video signal into PC 6 may be constructed in the form of commercially available, standard devices, well-known to specialists, for example, the AVER series.

Any suitable computer (preferably based on Pentium processors) may be used as the high-speed PC.

Synchronizer 7, which is shown in greater detail in fig. 5 and is later described in detail, may be realized on the basis of suitable frame and line sweep sync pulse selectors and suitable control clock and address pulse generators, known to electronics specialists.

In the form described, the proposed television system may be used as such for the needs, for example, of electronic archiving (in digital form) of large-format pictures (for example: aerial or x-ray photographs).

And, finally, when the proposed television system is used as a component of more complex systems (for example, x-ray diagnostic systems), it must have a converter 9 for converting electromagnetic radiation from one frequency range to another (in particular, converting X-radiation to visible radiation).

This converter 9 typically has the form of a not specially designated, primarily x-ray sensitive, fluorescent screen, or an xray optoelectronic transducer (XROET), or a scintillating fiber optic plate.

At the same time, the objectives of all video cameras 1 must be turned toward said converter 9 on its optical output side.

Correspondingly, a suitable primary (in particular, X-ray) radiation source 12 must be provided for in the system, placed at the optical input of converter 9, the selection of which for the needs of LuJI -o 0* roentgenoscopy or roentgenography does not present dificulties for specialists.

To facilitate adjustment, especially in cases of alteration of the number and/or relative arrangement of video cameras 1 and/or their distance to the object under examination or observation and/or converter 9, it is highly preferable that the following be included in the television system: calibration test objects 1 0 and a device 11I for placing them in the field of view of video cameras 1 during alignment and adjustment of the television system, and for removing them from the field of view of video cameras 1 before going into operating mode, connected to the synchronizing control output of synchronizer 7, and in order for synchronizer 7 to be connected with said PC 6 through the aforementioned data feedback loop; Calibration test objects 1 0 comprise three-dimensional targets, which are described in greater detail below.

Any suitable, commercially available manipulator or projector can be used as device 11 for placing and removing test objects 1 0, for example, a standard x-ray film cassette feed mechanism which has a fairly high (usually less than 1 mm) positioning accuracy.

A more complex high-resolution television system, which is preferable for the needs of x-ray diagnostics, may be additionallu equipped (see fig. 2): with the digital video signal amplitude corrector 1 3, which is connected to the input of multichannel geometric distortion corrector 3, with interframe digital video signal accumulators 1 4, the number of which is usually equal to the number of video cameras 1 and which are inserted in the interval between ADC module 2 and said digital video signal amplitude corrector 13, and with a multichannel threshold controller 1 The multichannel video geometric distortion corrector 3, in which the number of channels is equal to the number of video cameras 1, is a fundamentally new module for the proposed television system in any of its possible realizations, regardless of whether a specific realization provides for the use of calibration test objects 1 0 (vertical and/or horizontal three-dimensional targets) during -adjustment.

This corrector 3 is designed to combine ("stitch together") the Nfllds of view of different video cameras 1 into a unified high- I 4 24 resolution image field by elimination of geometric distortions of the fragmentary images, which may be due to differences in scales and shape of such images not usually noticed when viewed separately and inaccuracies in the mounting of individual video cameras 1.

In the simplest case, the individual optical parameters of the video cameras 1 and the geometric parameters of their specific relative arrangement should be taken into account beforehand in said corrector 3 as correction factors to be used later for correction of the video signals.

Later a more complicated version of the realization of the inventive conception is shown, providing for the use of two (vertical and horizontal) three-dimensional targets for automatic adjustment of the television system.

As applied to such cases, corrector 3 in each channel preferentially has at the input (see fig. 3): two identical calculation circuits 1 6 to calculate the codes for the corrected Xc and Yc coordinates for each pixel of the image output, based on the codes of the original coordinates X and Y of the corresponding pixels of the image input and the correction factors, and two identical slave memory modules 17 (possibly half-frame, but preferentially full-frame) for the digital video input, connected to said calculation circuits 16 as the sources for the addresses for readout of the information on the corrected elements of the video output.

Each of the calculation circuits 16 has: an input comparator 18 with fixed value of the threshold digital code Ut, connected to the output of one of the ADCs of module 2; a decoder (DC) 19, connected to an address output or Y) of the synchronizer 7 and having two control outputs; two AND logic circuits 20, each of which is connected to the output of comparator 18 and to the control output Ustr of synchronizer 7, and one of which is connected to the first control output of decoder 19 and the second of which is connected to the second control output of decoder 19; two nonvolatile RAMs 21 (NRAM), in which: the control (read-write and from here on designated inputs are independently connected to the outputs of the corresponding AND logic circuits It -the address and data inputs are also independently connected respectively to the X and Y outputs of synchronizer 7 so that in the 1st and 2nd RAM 21 of the first calculation circuit 16, the X signal is sent to the data inputs and the Y signal is sent to the address inputs, and vice versa in the 3rd and 4th RAM 21 of the second calculation circuit 1 6: the Y signal is sent to the data inputs and the X signal is sent to the address inputs; the differential stage 22 with two data inputs separately connected respectively to the data outputs of the nonvolatile RAMs (NRAM) 21, which is necessary for setting the codes of the final and initial abscissas Le(y) and Lb(y) in the first calculation circuit 1 6 and the codes of the final and initial ordinates HeWx and HbWx in the second calculation circuit 1 6 as the boundaries of the raster with respect to the test images of the three-dimensional targets when adjusting the television system; (preferably) a tabular normalizer 23, which provides integer division of the digital parallel code of one of the input X (or Y) signals by the digital code of the constant setting the geometric dimension of the undistorted raster LO along the horizontal (or Ho along the vertical) respectively for the first and second calculation circuits 16; a multiplier 24 for multiplying the digital codes of the normalized X (or Y) coordinate times the digital code of the active dimension of the raster along the horizontal (or the vertical) and an adder 25 for summing the digital codes of the coordinates of the origin of the representation of the distorted image field and the current increment in the coordinate of the processed picture element (pixel) in the same raster.

Each slave memory module 1 7 has: two input multiplexers 26, each of which (the first MXx for the X coordinate, and the second MXY for the Y coordinate) is designed to generate the corresponding digital codes for the coordinates of the pixels of the input and corrected images, and connected to them are RAMs 27 (possibly half-frame, but preferentially full-frame) for writing the video input to one address and reading the video output from another address.

Along with said calculation circuit modules 1 6 and slave memory modules 1 7 which are described in detail above, said corrector 3 at the output of each channel has (see fig. 3): -5.

C. 26 an inverter 28, which is connected between the abovementioned synchronizer 7 and the control inputs of multiplexers 26 and the RAM 27 of one of the slave memory modules 17; an output multiplexer 29, which is designed for alternate connection of the outputs of slave memory modules 17 to the input of video standards converter 4 with RAM.

The number of outputs of the decoders 19 (DC1 and DC2), the AND logic circuits 20, and the nonvolatile RAMs 21 (NRAM), shown in fig. 3, correspond to two lines of the three-dimensional targets for each of the calibration test objects 10. With an increase in the number of lines in the targets, the number of said outputs of decoders 19 and elements 20 and 21 should be accordingly increased, while between the outputs of RAMs 21 and the inputs of differential stages 22 additional multiplexers should be included, preferentially of the same type as multiplexers 26.

The video standards converter 4 with RAM (see fig. 4) has: independent RAM banks, the number of which is equal to the number of video cameras 1 and to each of which are connected: two address multiplexers 30 (MXA) and two frame buffers 31; control decoder 32 (DC) for RAM banks the first digital-to-analog converter 33 (DAC HRV); buffer RAM containing: memory modules 34 connected in parallel (RAM1-RAMN) the number of which is equal to the number of video cameras 1 and decoder 35 (DC CS) for the buffer RAM and the second digital-to-analog converter 36 (DAC TV).

For each of the aforementioned RAM banks, the following is characteristic: in frame buffers 31, the data inputs (DI) are combined and connected to the corresponding outputs (Uil 1, Ui12, UilNx, Ui21, Ui22, Ui2Nx, UiNyNx) of multichannel geometric distortion corrector 3, while the data outputs (DO) are also combined (including also between memory banks) and are connected to the data input of the first digital-to-analog converter 33; in multiplexers 30, the first inputs are combined and connected to the synchronizing outputs of synchronizer 7 with the codes of the X,Y coordinates for writing the corrected images to frame buffers 31, while the second inputs are also combined and connected to the synchronizing outputs of synchronizer 7 with the ~-r W 1. 2, 27 codes of the Xm,Ym coordinates for reading out the corrected images from frame buffers 31; the first outputs of the first multiplexer 30 are connected to the corresponding address inputs of the first frame buffer 31, while the first outputs of the second multiplexer 30 are connected to the corresponding address inputs of the second frame buffer 31; -the second control input of the first multiplexer 30 and the second inverted control input of the second multiplexer 30 are connected to the control output of synchronizer 7 (Urw); the first outputs of multiplexers 30 are connected to the address inputs their second outputs are connected to the select control inputs and their third outputs are connected to the control outputs of the corresponding RAMs 31.

In all the RAM banks, the first control inputs of the first and second multiplexers 30 are combined and connected respectively to the first, second, etc. outputs of decoder 32.

The control input of decoder 32 is connected to the control output (Ucj) of synchronizer 7.

In all the RAM banks, the data outputs (DO) of all frame buffers 31 are combined and connected to the data input of the first digitalto-analog converter 33 (DAC HRV).

In the first digital-to-analog converter 33 (DAC HRV): the first and second control inputs are respectively connected to the synchronizing outputs (HHSI) and (HVSI) of synchronizer 7, while the data output (Uout) is connected to the above-mentioned high-resolution monitor 8.

In each memory module 34 (RAM1-RAMN) of the buffer RAM: the address inputs are combined and connected to the synchronizing outputs of synchronizer 7 with the codes for the X,Y coordinates; the data inputs (DI) are connected to the corresponding outputs of the multichannel geometric distortion corrector 3; the data outputs DO are combined and connected to the data input of the second digital-to-analog converter 36 and the control inputs are connected to the control output of synchronizer 7. Furthermore, the data input (DI) of the last memory module 34 RAMN is connected to the corresponding data input (DI) of frame buffer 31 (RAMNyNx).

28 The control and (Uw) inputs of decoder 35 (DC CS) of the buffer RAM are connected to the corresponding control outputs of synchronizer 7.

The control outputs of said decoder 35 are connected to the select inputs (CS) of memory modules 34 so that the first of said outputs is connected to said input of the first module 34, the second is connected to the input of the second module 34, etc.

In the second digital-to-analog converter 36 (DAC TV): the data input is connected to the combined data outputs (DO) of memory modules 34, the control inputs (HSI) and (VSI) are respectively connected to the synchronizing outputs of synchronizer 7, while the data output Upc is connected to module 5 for inputting the video signals into the computer.

Synchronizer 7 has (see fig. a sync pulse selector 37, which is designed to extract from the total input video signal (Uinl) the original synchronizing pulses and to generate output line horizontal- HSI) and half-frame vertical VSI) synchronizing pulses, and is connected: through the input to the synchronization output of one of the video cameras 1, while through the synchronizing outputs (HSI) and (VSI) to respectively the control inputs of digital-to-analog converter 36 of video standards converter 4 with RAM described above (shown in fig.

4); a frame pulse selector 38, the inputs of which are connected respectively to the outputs of the line (HSI) and half-frame (VSI) synchronizing pulses of selector 37, while the output Uki is connected to the synchronizing input of the multichannel threshold controller 15 described in detail later; a counter T flip-flop 39 the input of which is connected to the output of selector 38, while its output is connected to the control inputs of multiplexers 30 of video standards converter 4 with RAM (shown in fig. 4); a driving generator 40 of the synchronizing ("TV sync") signals, corresponding to the resolution standard of video cameras 1, the output (fl) of which is connected to the clock inputs of the above-mentioned ADC modules 2 and the multichannel threshold controller 15 and which is built, for example, on the basis of a suitable commercially available quartz resonator; 29 a generator of the codes for the X and Y coordinates, not distinguished and not specially designated, which is built on the basis of: -counter 41 (CTX) for counting the number of pixels per line of the image for each of the video cameras1, in which the count input is connected to the output of TV sync generator 40, while the reset input is connected to the output (HSI) of sync pulse selector 37, and counter 42 (CTY) for counting the number of lines in the images formed by each of the video cameras 1, the count input of which is connected to the output (HSI) of sync pulse selector 37; a driving generator 43 of the synchronizing signals corresponding to the high-resolution standard (HRV) of the synthesized high-resolution image output and built,, for example, on the basis of an appropriate commercially available quartz resonator; a counter 44 (CTXm) for counting the number of pixels per line of the synthesized image, in which: the count input is connected to the output of said generator 43 (sync-HRV), the reset input is connected to the output (HSI) of sync pulse selector 37, the first output (Xm) is connected to the synchronizing input while the second output (Udc) is connected to the control input of the video standards converter 4 with RAM described above; a digital comparator 45 (HHSI): connected through the data input to the second output (Udc) of counter 44 (CTXm) for counting the number of pixels per line of the synthesized high-resolution image and designed for sequential comparison of the codes for the coordinates (Xm) of the active pixels in a line of the synthesized high-resolution image with fixed threshold code Nx of the coordinate for the end of the line of the given image, determined by the number of video cameras 1 disposed horizontally in a row; preferably, a monostable multivibrator 46 (HHSI) for generation of the line sync pulses for the video signal of the synthesized high-resolution image, in which: the input can be connected to the control output of said counter 44 (CTXm) for counting the number of pixels per line of the synthesized high-resolution image, while I I.

the output (HHSI) can be connected to the control input of the above-mentioned video standards converter 4 with RAM; counter 47 (CTYm) for counting the lines of the synthesized high-resolution image, in which: the count input is connected to the output of said monostable multivibrator 46 (HHSI), the reset input is connected to the output (VSI) of thesync pulse selector 37, and the output (Ym) is connected to the synchronizing input (Ym) of video standards converter 4 with RAM; a digital comparator 48 (HVSI) is connected through the data input to the output (Ym) of counter 48 (CTYm) for counting the number of lines in the synthesized high-resolution image and -is designed for sequential comparison of the codes for the coordinates (Ym) of the lines of the synthesized high-resolution image with fixed threshold code Ny for the coordinate of the end of a frame of the given image, determined by the number of video cameras 1, disposed vertically in a column; preferably, a multistable monovibrator .49 (HVSI) for generation of frame sync pulses for the video signal of the synthesized high-resolution image, which may be connected: through the input to the output of comparator 48, while through the output (HVSI) to the control input of the abovementioned video standards converter 4 with RAM; counter 50 (CTUcb) for controlling the readout from the buffer RAM of the video standards converter 4 with RAM when inputting the synthesized image to PC 6, in which the count input is connected to the output of said monostable multivibrator 49 (HVSI); two AND logic circuits 51 for performing the conjunction operation for generation of the control signals Ustr and Uc, sent respectively: to multichannel geometric distortion corrector 3 for switching nonvolatile RAMs 21 (NRAM) to write or read modes for writing or reading the codes for the coordinates of the boundaries of the test images when adjusting the system and to interframe accumulators 14 for terminating the accumulation when adjusting the system. In order to do this, the first inputs of the logic circuits are combined and connected to the output (fl) of driving generator 40, the output (Ustr) of the first AND circuit 51 is connected to the corresponding control input of the ~il ir ;i above-mentioned geometric distortion corrector 3, while the output (Uc) of the second AND circuit 51 is connected to the combined control inputs of the interframe accumulators 1 4; a D flip-flop 52, which is designed for synchronizing the start of generation and setting the duration of the control signal Uc sent to the interframe accumulators 14, and in which: -the synchronizing input is connected to the output of frame pulse selector 38, the data input is connected to the control output (Usn) Of multichannel threshold controller 1 5 described in detail later, while the inverted output is connected to the second input of the second AND circuit; an input register 53 (RG D) for synchronizer 7 to receive the control commands sent from PC 6, in which: the parallel data input is connected to the data bus of PC 6, the first output (Uw) is connected to the reset input of counter 50 (Uc~c) and the control input of video standards converter 4 with RAM, the second output (Ucib) is connected to the second input of the first AND circuit and to the control input of the abovementioned device 11 for positioning the test objects in the field of view of the video cameras (see fig. and the third output is connected to the reset input of D f lipflop 52; an output register 54 (RG 0) for outputting information on the state of synchronizer 7 to PC 6, in which: -the first input is connected to the output (VSI) of the abovementioned sync pulse selector 37, the second input is connected to the output Udcr_ of counter while the output is connected to the data bus of PC 6; an address decoder 55 (DC A) for the programmable port of PC 6 for outputting the control commands to synchronizer 7, in which: the input is connected to the address bus of PC 6, while the output is connected to input C of input register 53.

Multichannel digital video signal amplitude corrector 1 3 as a whole is designed for matching the video signals of video cameras 1 with respect to amplitude parameters (usually with respect to excursion and "black" level) mainly during lengthy roentgenoscopic examinations or when monitoring surgical operations. This corrector S~Y~r~ 'S '4 32 13 is a set of channels with isolated inputs, the number of channels of which is equal to the number of video cameras 1, and in each channel (see fig. 6) there are: preferentially two nonvolatile RAMs 56 (NRAM1) and 57 (NRAM2) which are respectively designed for storing the codes of the correction factors for the "black" level and the maximum excursion of the video signal for each pixel of the image input from the video camera 1 corresponding to the given channel; a differential stage 58 for calculating the difference between codes for the input signal Ui(x,y) and the "black" level Ub(x,y) for each pixel of the image input from the corresponding video camera 1; a divider 59 for calculating the normalized amplitude correction factors for the video input signals by dividing the constant setting (for the selected video cameras 1 and ADCs 2) the code Umax for the maximum excursion of the video signal, by the varying code Uw(x,y) corresponding to the maximum excursion of the video signal for each active pixel of the image input from the corresponding video camera 1; an address decoder 60 (DC) for the programmable port of PC 6, for outputting the control commands to the given channel of the digital video signal amplitude corrector 13, in which the input is connected to the address bus of PC 6; an input register 61 (RG) for receiving the control commands coming from PC 6, for which: the first input is connected to the data bus of PC 6 and the second input is connected to the output of address decoder 60, while the outputs are connected to the control inputs of nonvolatile RAMs 56 and 57 an output multiplier 62 for generating the codes for the normalized video output Ucu(x,y) by multiplication of the aforementioned normalized factors times the code for the difference signal.

As previously stated, in the case of this preferred realization of digital video signal amplitude corrector 13, besides what has been indicated, the above-mentioned functional modules have the following external connections and interconnections: RAM 56 (NRAM1) is connected: -through the data input to the output of the corresponding channel of the above-mentioned ADC module 2, through the control input to the first output of input register 61 (RG), 33 RAM 57 (NRAM2) is connected: through the data input to the output of said differential stage 58, through the control input to the second output of input register 61 while through the address inputs, both RAMs 56 and 57 (NRAM 1 and 2) are connected to the X,Y output of the above-mentioned synchronizer 7; differential stage 58 is connected: through the first input to the output of the corresponding channel of the above-mentioned ADC module 2, through the second input to the output of said RAM 56 (NRAM 1), -through the output to the first input of said multiplier 62; divider 59 is connected between the output of RAM 57 (NRAM2) and the second input of multiplier 62.

It is clear to specialists that, in principle, we can manage with one nonvolatile RAM (NRAM) with insignificant losses in the quality of the amplitude correction.

Each interframe accumulator 14 (see fig. 7) has: two multipliers 63 and 64, which respectively are designed for multiplying the code Uin(x,y) for each active pixel of the image input times the weighting factor Ak, and multiplying the code Ui(x,y) for each pixel of the accumulated image times the weighting factor Bk; and the first input of multiplier 63 is connected to the output of the corresponding channel of the above-mentioned ADC module 2; an adder 65 for calculating the weighted sum of the codes for each active pixel of the image input and the corresponding pixel of the accumulated image, in which the first and second inputs are connected respectively to the outputs of multipliers 63 and 64; a RAM module 66 for storing the codes Ui(x,y) of the pixels of the accumulated image, in which: the first input is connected to the output of adder the second input is connected to the synchronizing outputs of the above-mentioned synchronizer 7 with the codes of the X,Y coordinates, the third input is connected to the control output Uc of the above-mentioned synchronizer 7, while the data output Ui(x,y) is the output of the interframe accumulator and is connected: A-

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34 to the input of the corresponding channel of the abovementioned digital video signal amplitude corrector 1 3 (see fig. 6), and to the first input of multiplier 64; an address decoder 67 (DC) for the programmable port of PC 6 for outputting to the interframe accumulator 1 4 the codes for the weighting coefficients Ak and Bk, in which the input is connected to the address bus of PC 6; an input register 68 (RG) for receiving the codes of the weighting factors Ak and Bk, sent from PC 6, in which the first input is connected to the data bus of PC 6 while the second input is connected to the output of address decoder 67, the first output i s connected to the second input of multiplier 63, while the second output is connected to the second input of multiplier 64.

The interframe accumulators can be easily selected by specialists from a wide variety of commercially available products of this type.

Multichannel threshold controller 1 5 as a whole is designed for controlling: (directly) source 1 2 of primary x-radiation according to the criteria of permissible absorbed dose and the required quality of the synthesized integral image, mainly in mass roentgenographic examinations, and (through the above-mentioned synchronizer 7) interframe accumulators 1 4.

It is a set of channels with isolated inputs, the number of channels being equal to the number of video cameras 1, and in each channel (see fig. 8) there are: a first comparator 69 for comparing the codes for the pixels of the image formed by the video camera 1 corresponding to the given channel with the threshold code Ui; an AND circuit 70, which is connected to the output of comparator 69 through the first input and is designed for strobing the clock signal fj with the output signal of this comparator; a counter 71, the count input of which is connected to the output of the AND circuit 70 and which serves for counting the number of such pixels in the image f rame corresponding to the video camera 1 connected to the given channel, the codes of which exceed the threshold U1 a register 72 the data input of which is connected to the output of counter 71 and which serves for storing the parallel output code of this counter; a second comparator 73, which is connected to the output of counter 71 through register 72 and serves for comparison of the output code of this counter 71 with the threshold Ui11; a trigger 74, in which the D-input is connected with the output of comparator 73 and which serves for writing the logical output signal of this comparator at the end of the synchronizing frame pulse Uki from the above-mentioned synchronizer 7.

Furthermore, for all the channels of the multichannel threshold controller 1 5, the following general functional modules are provided, also shown in fig. 8: an address decoder 75 (DC) for the programmable port of PC 6 for outputting to multichannel threshold controller 1 5 the threshold codes U1, U 1 1 and UI 2 in which the input is connected to the. address bus of PC 6; an input register 75 (RGD) for receiving the codes for the thresholds U1, U 1 1, and U sent from PC 6, in which: the first input is connected to the data bus of PC 6, while the second input is connected to the output of address decoder -the first output is connected to the combined first inputs of the above-mentioned comparators 69 for all the channels, while the second output is connected to the combined second inputs of the above-mentioned comparators 73 for all the channels; a multiplexer 77 (MX) for multiplexing the output signals of all the channels, in which: -each data input is connected to the outputs of 'triggers 74 of the corresponding channels, while the control input is connected to the synchronizing output of the above-mentioned synchronizer 7 with the code for the X coordinate; an AND circuit 78 for strobing the clock signal fj with the output signal of multiplexer 77, in which: the first input is connected to the output o f multiplexer 77, the second input is -connected to the combined second inputs of the AND circuits 70 of each of the channels of the multichannel threshold controller 1 5 and is connected to the output of driving generator 40 of the synchronizing ("TV sync") signals (see I "r 36 fig. to the clock output of the above-mentioned synchronizer 7; a counter 79 for counting the number of channels for which the signals at the outputs of triggers 74 have logic level and which is connected: through the count input to the output of AND circuit 78, while through the reset input to the synchronizing output Uki of the above-mentioned synchronizer 7 through inverter a comparator 81, designed for comparing the output code of counter 79 with the threshold UI 2 and connected: through the first input to the output of counter 79, -through the second input to the third output of the abovementioned input register 75 (RGD), and through the output to the not specially shown controller of source 12 of primary (x-ray) radiation (see fig. 2); a trigger 82 forrecording and storing the output signal of comparator 81, connected through the D input to the output of this comparator 81, through the clock input across said inverter 80 to the synchronizing output Uki of the above-mentioned synchronizer 7 (see fig. and through the output Usn to the D input of trigger 52 of the above-mentioned synchronizer 7.

Furthermore, in each channel the following inputs are combined and jointly connected to the synchronizing output Uki of the above-mentioned synchronizer 7: the reset input of each counter 71, the clock input of each register 72, and the clock input of each trigger 74; And, finally, the second inputs of comparators 69 of all the channels of the multichannel threshold controller 15 are connected to the corresponding data outputs Ucul(X,Y)...UcuN(x,y) of the abovementioned digital video signal amplitude corrector 13.

The test objects 10 with vertical (see fig. 9) and horizontal (see fig. 10) positioning of the three-dimensional targets are similar in construction and contain a rigid rectangular board 83 made of x-ray transparent material, such as ordinary glass or plexiglass, and thin cords (filaments) 84 made of x-ray opaque material such as steel are embedded in the board or stretched over it. A rigid frame can be used instead of the board.

The format of board (or frame) 83 corresponds to the format of the total field of view, while its dimensions are greater than the dimensions of the total field of view of all the video cameras 1.

The cords 84 are positioned beforehand so that the field of view of each of the video cameras 1 is approximately delimited during adjustment, while after adjustment it is clearly delimited by two adjacent cords respectively along the horizontal for the first test object 10 and along the vertical for the second test object In this case, each internal cord 84 (not on an edge) simultaneously delimits the field of view of two adjacent video cameras 1 due to partial (up to overlap of their fields of view.

In particular, one of the test objects has Nx+1 vertical cords 84 while the second test object has Ny+1 horizontal (in the operating position) cords 84, where Nx and Ny are respectively the number of video cameras 1 positioned along the horizontal and the vertical in the form of a three-dimensional grid. In this case, the product Nx*Ny N, the total number of video cameras 1.

In figs. 9 and 10, as an example we show diagrams for calibration test objects 10 for cases when Nx 3 and Ny 3, and N 9.

Independently of the specific realization of the inventive conception, use of the proposed high-resolution television system involves the following: preparation for operation, by at least adjusting geometric distortion corrector 3 to yield certain correction factors, and operation proper, providing for the formation from the fragmentary video input signals of video cameras 1 a video output signal, corresponding to the integral image and, as needed, digital recording of the video output signal for subsequent analysis.

Preparation for operation begins with mounting video cameras 1 on an arbitrary rigid support so that their fields of view partially overlap, while their aggregate field of view overlaps the area of image converter 9.

In the simplest case, when the composition and structure of the proposed television system corresponds mainly to fig. 1 and when modules 10, 11, and 12 are not included in it, geometric distortion corrector 3 should be adjusted beforehand by the operator.

In order to do this, all the video cameras 1 should be examined on a test bench (which is a trivial matter for specialists to assemble) and the geometric distortions intrinsic to each of them should be quantitatively determined.

i. I 38 Based on the data obtained, using a familiar algorithm (such as the algorithm for minimization of the mean-square deviation of an observed image from the required image), taking into account information on the relative arrangement of video cameras 1 within a single unit, the distance to the observed object and, as needed, such factors as the average luminance of the observed object, the correction factors should be calculated for elimination of-geometric distortions and correction of the video output signal.

The correction factors obtained then should be written to the nonvolatile memory of geometric distortion corrector 3, which makes it possible to proceed from adjustment to use of the proposed television system specifically under the conditions for which the video cameras 1 were examined and the correction factors were calculated.

The essence of the correction for geometric distortions and the meaning of the calculations will become clearer from a detailed description of the algorithm for automatic adjustment in a more complicated but preferable case, when the proposed television system corresponds to fig. 2 and is used mainly as an x-ray television system for real-time monitoring of physiological (mainly fast) processes.

In this case, preparation for operation involves automatic adjustment of geometric distortion corrector 3 and preferably digital video signal amplitude corrector 13.

Automatic adjustment of corrector 3 begins with sequential positioning of x-ray contrast vertical and horizontal calibration test objects 10 between image converter 9 and source 12 of primary xradiation according to the command of PC 6, sent through synchronizer 7 to device 11.

Synchronously operating video cameras 1 read the image formed by converter 9 over its entire area with partial mutual overlap of the fields of view of the individual video cameras 1.

Shadows from cords 84 of test objects 10 (see figs. 9 and in the field of view of each video camera 1 have the form of fine (usually two) lines: respectively vertical for each video camera 1 in each horizontal row, and horizontal for each video camera 1 in each vertical row. The distances between lines are determined respectively by the expressions: LI-L/N (1) 39 where L is the horizontal dimension of the total image field; LI is the horizontal distance between lines Nx is the number of video cameras 1 in a horizontal row, and HI H/Ny, (2) where H is the vertical dimension of the total image field; HI is the vertical distance between lines Ny is the number of video cameras 1 in a vertical row.

The lines of each test object 10 partition the image field into rectangles, to each of which corresponds the field of view of one of the video cameras 1. The optical systems of video cameras 1 are aligned consecutively and video cameras 1 are fixed so that in the field of view of each of them when observing the first test object the vertical lines are located close to the left and right boundaries, while the horizontal lines are located close to the upper and lower boundaries of the field of view.

The video signal of each video camera 1 in corrector 3 is sent to the two comparators 18 corresponding to it (see fig. which compare the code of said video signal with the fixed threshold code Ut and detect respectively the vertical and horizontal lines (the boundaries of the raster) on the images of test objects 10. In this case, the first decoder 19 delimits the detection zone for the initial and final lines on the images of test objects 10 with respect to the X coordinate, and the second decoder 19 does the same with respect to the Y coordinate.

When comparator 18 detects a line (a shadow from cord 84) in a specified zone, the control signal Ustr generated by the synchronizer 7 through the corresponding AND circuit 20 is sent to the control input of nonvolatile RAMs (NRAM) 21. In this case, the first and second NRAM 21 respectively fix the initial Lb(y) and the final Le(y) abscissas of the boundary of the raster with respect to the first test object 10, while the third and fourth NRAM 21 fix the initial Hb(x) and the final He(x) ordinates of the boundary of the raster with respect to the second test object To do this, synchronizer 7 sends the code for the Y coordinates to the address inputs of the first and second NRAM 21 and, on the other hand, sends the code for the X coordinate to the data inputs of the first and second NRAM21, while it sends the code for the X coordinate to the address inputs of the third and fourth NRAM 21 and, on the other hand, sends the code for the Y coordinate to the data inputs of the third and fourth NRAM 21.

After said values Lb(y), Le(y), Hb(x), and He(x) have been recorded, device 11 removes the last of the calibration test objects from the field of view of video cameras 1, the control signal Ustr generated by synchronizer 7 switches all NRAM 21 to readout mode, and the automatic adjustment of corrector 3 is completed.

Said values of Lb(y) and Le(y) then serve for correction of a fragment of the image output by calculating the Xc coordinates of the pixels along the horizontal, and the values of Hb(x) and He(x) serve for correction of a fragment of the image output by calculating the Yc coordinates of the pixels along the vertical.

The essence of such correction, necessary in any possible operating modes of the proposed television system, mainly reduces to carrying out the following operations.

The codes for the Xc and Yc coordinates of the pixels of the corrected image are calculated by differential stages 22, tabular normalizers 23, multipliers 24, and adders 25 of the first and second above-mentioned calculation circuits 16, respectively, according to the following algorithm: Xc(y) Lb(y), (3) Yc(x) HLb(y), (4) where Lo and Ho are respectively the undistorted horizontal and vertical dimensions of the image for each video camera 1.

The codes of the pixels for the corrected image Uic(x,y) are read out from RAM 27 of one of the two slave memory modules 17 in accordance with the calculated coordinates Xc and Yc.

Simultaneously with readout, the codes for the pixels of the original image Ui(x,y) are written to RAM 27 of the second slave memory module 17 at the addresses X and Y, sent from synchronizer 7.

The addresses for writing to and reading from RAM 27 of the first and second slave memory modules 17 are generated by multiplexers 26.

Multiplexers 26 and RAM 27 of the first slave memory module 17 are controlled by the signal Urw of synchronizer 7, while multiplexers 26 and RAM 27 of the second slave memory module 17 are controlled by the inverted signal Urw from the outputs of inverters 28.

In this case, the first and second slave memory modules 17 operate in opposite phase: when the first modules are reading the codes for pixels of the corrected image from the Xc and Yc addresses, the second modules are writing the codes for pixels of the original image to the X and Y addresses, and vice versa.

Alternation of the "read-write" cycles occurs at a frequency equal to the frame rate of video cameras 1.

Output multiplexer 29 multiplexes signals from the outputs of RAM 27 of the first and second slave memory modules 17 in accordance with the logic level (0 or 1)of the signal Urw from synchronizer 7.

As has already been noted, after adjustment of all the channels of geometric distortion corrector 3, it is advisable to adjust the digital video signal amplitude corrector 13 (see fig. 6) immediately.

When such adjustment begins, source 12 of primary (x-ray) radiation is turned off. ADC module 2 for each of the video cameras 1 generates the codes for the readouts (min)Ui(x,y), corresponding to the "black" level of the video output signal.

In each channel of said corrector 1 3, according to the control commands from PC 6 sent through input register 61 for each pixel of the fragmentary image said codes are written to nonvolatile RAM (NRAM) 56 in accordance with the X and Y addresses which are generated by synchronizer 7. Accordingly, in all channels of corrector 13 provision is made for writing such codes for the entire image field. After writing, the nonvolatile RAMs (NRAM) 56 in all channels of corrector 13 are switched to read mode according to the command of PC 6.

Then said codes will be directly used as correction factors Ub(x,y), determining the "black" level in correction of fragments of the integral video output signal.

Analogously, after connecting source 12 of primary (x-ray) radiation, ADC module 2 for each of the video cameras 1 generates codes for the readouts (max)Ub(x,y), corresponding to the maximum excursion of the video output signal. Then in each channel of said corrector 13, according to the control commands from PC 6 sent through the same input register 61 the following occur for each pixel of the fragmentary image: in differential stage 58: subtraction (max)Ui(x,y) while 'I 1 42 in nonvolatile RAM (NRAM) 57, the difference between said codes is recorded in accordance with the addresses X and Y, which are generated by synchronizer 7. Accordingly, in all channels of corrector 13, provision is made for writing such codes for the entire image field.

The differences obtained then will be used during correction as the correction factors Uw(x,y), determining the maximum excursion of the fragments of the integral video output signal.

After these factors have been written to RAM 57 of all channels, these RAMs according to commands from PC 6 are switched to read mode, and adjustment of digital video signal amplitude corrector 13 is completed.

The essence of the amplitude correction, which is necessary when using the proposed television system for x-ray diagnostics of parts of the human body which have different x-ray transmission coefficients, and especially when using automatic control of the irradiation dose (and in the remaining cases, it is just desirable), involves mainly the following.

In each channel of video signal amplitude corrector 13, for each point with coordinates of the images formed by each video camera 1, the following operations should be performed as specified by the expression: Ucu(x,y)-Ui where Ucu(x,y) is the corrected video signal at the output of corrector 13; Ui(x,y) is the code for the video signal at the input of corrector 13; Umax is the code for the maximum excursion of the video signal for the synthesized integral image; Ub(x,y) and Uw(x,y) are the codes for the correction factors, the physical meaning of which and methods for obtaining which are given above.

Subtraction from the code for the video input signal Ui(x,y) of the corresponding code for the "black" level (as the correction factor Ub(x,y), read from nonvolatile RAM (NRAM) 56), is done in differential stage 58. Performing this operation with the video output signals of all the video cameras 1 makes it possible to set a single value for the code for the "black" level for the video signal of the synthesized integral image, I -II-IIII- Ill lilt i The result of integer division of the code for the maximum excursion of the video signal for the synthesized integral image by the code for the maximum excursion of the fragmentary video signal (the correction factor Uw(x,y), read from nonvolatile RAM (NRAM) 57), is sent to multiplier 62 from the output of divider 59. Thus divider 59 and multiplier 62 reduce the fragmentary video signal to a common scale, corresponding to the synthesized integral video signal.

In operating mode, the proposed high-resolution television system can function as follows.

In the simplest case, such as when forming high-resolution television images of the Earth's surface based on cartographic images on photographic film obtained by aerial or space photography, the original image is directly projected onto the optical systems of video cameras 1.

ADC module 2 converts the video output signals of video cameras 1, corresponding to the fragmentary images, to digital form in the familiar way and supplies them to the inputs of geometric distortion corrector 3.

This corrector 3, as was described above, eliminates those distortions of the video signals of the fragmentary images which hinder their "stitching" into an integral image without visible boundaries between fragments.

Synthesis of the high-resolution integral image occurs in video standards converter 4 with RAM (see fig. to which the corrected fragmentary video signals are sent from corrector 3 through the combined data.inputs (DI) of all frame buffers 31 of the independent RAM banks.

Formation of the high-resolution integral image begins with parallel writing of said video signals to the first frame buffers 31 at the X and Y addresses, supplied from the above-mentioned synchronizer 7 through the very first address multiplexers 30. To do this, control decoder 32 for the RAM banks generates control signals and sends them to each of the first RAMs 31 through the first multiplexers 30 corresponding to them. According.to these signals at the inputs, the first RAMs 31 switch to write mode, while the signals at the (CS) inputs maintain the outputs (DO) of the same RAMs 31 in a high impedance state. Thus each first frame buffer 31 records the first active frame of the corrected television image of the corresponding video camera 1.

The next active frame of such an image analogously will be written to the second frame buffer 31 of all the independent RAM banks, with the distinctions that the signals of the X and Y addresses from the above-mentioned synchronizer 7 and the abovementioned other control signals from decoder 32 will be supplied through the second address multiplexers.

In the same time period, the first frame buffers 31 of all the.

independent RAM banks will operate in sequential read mode for readout of the lines of the fragmentary corrected video signals of the preceding frame in accordance with the addresses Xm and Ym, supplied from synchronizer 7 through the first address multiplexers In this case, the outputs (DO) of the first frame buffers 31 are sequentially switched to the active state by the control signals, which are supplied to the inputs (CS) from the above-mentioned decoder 32 through the corresponding first multiplexers Sequential readout is done as follows: when the first line of the frame of the above-mentioned video cameras 1 begins to be written to the second frame buffers 31, simultaneously the outputs (DO) are switched to the active state in the first frame buffer 31 of the RAM bank which corresponds to the video camera 1 located in the first column and the first row, and the first line of the preceding frame written in it is read out; then the outputs (DO) of said first frame buffer 31 are switched to the high-impedance state, and the outputs are switched to the active state in the first frame buffer 31 of the next RAM bank, which corresponds to video camera 1, located in the second column and the first row, and the first line of the preceding frame written to it is read out; said operations are repeated until the first lines of the preceding frame are read out from the first frame buffers 31 of all the RAM banks corresponding to video cameras 1 which are located in the first row, again the outputs (DO) are switched to the active state in the first frame buffer 31 of the RAM bank, which corresponds to the video camera 1 located in the first column and the first row, and the second line of the preceding frame is read out; during parallel writing of the first line of the active frame to the second frame buffers 31 of all the RAM banks, the number of lines Ny (which is equal to the number of rows of video cameras 1) are read out from the first frame buffers 31 of those RAM banks ,-which correspond to video cameras 1 located in the first row; I( f when writing of the second line of the active frame to the second frame buffers 31 begins, switching of the outputs (DO) of the first frame buffers 31 to the active state and readout of the lines of the preceding frame occur analogously, but starting from the (Ny+i)-th line; after readout from the first frame buffers 31 of the RAM banks corresponding to video cameras 1 located in the first row is finished, the lines of the preceding frame are analogously read from the RAM banks which correspond to the second row of video cameras 1, and so forth.

Then parallel writing of the third and subsequent active frames and sequential readout of the second and subsequent active frames of the corrected television images of the corresponding video cameras 1 are repeated many times, with alternation of the participating first and second frame buffers 31 of all the independent RAM banks.

Then digital-to-analog converter 33 (DAC HRV) converts the digital code corresponding to the high-resolution integral image, supplied from the outputs DO of frame buffers 31, to the analog video signal UoLt.

Simultaneously with writing to frame buffers 31, buffer RAM modules 34 (RAM1...RAMN), according to the signal Uw of one logic level supplied from PC 6 through synchronizer 7, write in parallel the corrected fragmentary video signals of video cameras 1 for their subsequent input into PC 6. In this case, the outputs (DO) of memory modules 34 are found in the high-impedance state in accordance with the control signals from the outputs of buffer RAM decoder (DC CS). When the high-resolution image written to the buffer RAM is inputted, on the other hand, into PC 6, modules 34 are switched to read mode by the command Uw of the other logic level, and the control signals from the outputs of decoder 35 alternately switch the outputs (DO) of these modules 34 to the active state.

The video output signal of video standards converter 4 with RAM is sent through module 5 to PC 6 for documentation, archiving, or displaying on its own monitor (for inspection) and/or on the highresolution monitor 8 (for online inspection or preliminary visual assessment).

For the described application of the proposed television system, the system control functions are successfully managed by PC 6 and synchronizer 7, in which (see fig. a) selector 37 extracts the original sync pulses from the total television input signal Uinj and on the basis of these pulses generates: output line HSI and half-frame VSI synchronizing pulses, used then in the digital-to-analog converter 36 of the above-mentioned video standards converter 4 with RAM to generate the total television signal, sent to module 5 for inputting to PC 6; b) frame (sync) pulse selector 38 and flip-flop 39 generate the control signal Urw for address multiplexers 30 of the abovementioned video standards converter 4 with RAM for generation in this converter (see fig. 4): read and write addresses, control signals for the operating modes of frame buffers 31, including chip select commands (CS) and read/write (r/w) commands, and control signals for input multiplexers 26 and read/write modes of RAM 27 in slave memory modules 17 of the abovementioned geometric distortion corrector 3; c) TV sync generator 40 generates the clock signal fl, which is sent: to the above-mentioned ADC module 2 for setting the timing of the "analog-to-code" conversions in the analog-to-digital converters included in this module and to the count input of counter 41 for generation of the codes for the abscissas X of the pixels of images in video cameras 1; d) counter 42, according to the signals of the line HSI synchronizing pulses of sync pulse selector 37, generates the codes for the ordinates Y of the pixels of images of video cameras 1; (then said codes for the coordinates X and Y are sent: to the data inputs of address multiplexers 30 as addresses for writing to frame buffers 31 in the operating mode, to the address inputs of memory modules 34 of the abovementioned converter 4 upon input of the video signal of the synthesized image to the above-mentioned PC 6 through input module 5 and to the above-mentioned geometric distortion corrector 3, including: to calculation circuits 16, to the data inputs of decoders 19 for generation of control signals for the read/write modes of the nonvolatile RAMs 21 (NRAM) and to the address inputs of these RAMs for readout of the values of Lb(y), Le(y), Hb(x), and He(x) recorded during adjustment, which are needed in calculating the codes for the corrected coordinates Xc and Yc in the operating mode, and to slave memory modules 17, to the inputs of multiplexers 26 for generation of the addresses for writing the codes of the video signals of video cameras 1 in the operating mode); e) counter 44, according to the signals from sync-HRV generator 43 generates the codes for: the abscissas Xm for the pixels of the synthesized image and the control signal Ud, sent to decoder 32 for controlling the RAM banks of the above-mentioned video standards converter 4 with RAM, for selection of the RAM bank when reading out the previously written codes for the pixels of images of video cameras 1 in formation of a high-resolution integral image in the operating mode; f) comparator 45 HHSI and monostable monovibrator 46 HHSI generate line (HHSI) sync pulses for the video signal of the synthesized image; g) counter 47, according to the line (HHSI) sync pulse signals from the output of the above-mentioned monostable multivibrator 46, generates the codes for the ordinates Ym for the pixels of the synthesized image, which together with the above-mentioned codes for the abscissas Xm for the pixels of this image are sent to the data inputs of address multiplexers 30 of the above-mentioned video standards converter 4 with RAM as the addresses for readout from frame buffers 31 in the operating mode in formation of the synthesized integral image on the above-mentioned monitor 8; h) comparator 48 HVSI and monostable multivibrator 49 HVSI generate the frame (HVSI) sync pulses for the video signal of the synthesized image, which together with the above-mentioned line (HHSI) sync pulses from the output of the above-mentioned monostable multivibrator 46 are sent to digital-to-analog converter 33 of the above-mentioned video standards converter 4 with RAM for formation in the operating mode of the total television video signal U=t of the synthesized high-resolution integral image; i) counter 50, according to signals from the frame (HVSI) sync pulses, generates the control signal Udc, sent to decoder 35 of the buffer RAM for selection of the memory module 34 which is active at the given time for input of the video signal of the synthesized integral image to the above-mentioned PC 6; j) input register 53, according to the synchronizing signal of address decoder 55 (DC A) for the programmable port of PC 6, receives commands from this PC and on the basis of these commands -ns generates: the control signal Uw, enabling input of the video signal of the synthesized high-resolution integral image to PC 6, that is sent to the above-mentioned video standards converter 4 with RAM, the control signal Ucib for triggering the adjustment mode, that is sent: to the above-mentioned device 11 to start positioning the above-mentioned calibration test objects 10 in the field of view of video cameras 1 (during automatic adjustment of the television system), and -toAND circuit 51, which based on this signal generates the control signal Ustr, sent to geometric distortion corrector 3 for switching nonvolatile RAMs 21 (NRAM) to write mode for writing the codes for the coordinates of the boundaries of the test images (during automatic adjustment of the television system); k) output register 54 sends to the above-mentioned PC 6 a frame (sync) pulse signal, generated by frame pulse selector 38, and the control signal Udo from the output of the above-mentioned counter The functioning of the other modules of synchronizer 7 will be described below as applied to other possible operating modes of the proposed television system, mainly for the needs of x-ray diagnostics,- when it is advisable to use interframe accumulators 1 4 and multichannel threshold controller 1 5 in order to increase the quality of the integral images.

One such mode is motivated, for example, by the requirement for automatic adjustment of said system for roentgenoscopic monitoring of surgical operations using probes. 'In fact, in preparing the (x-ray) television system for such operations, often it is necessary to change the relative disposition of video cameras 1, taking into account the required configuration and the area of the operative field.

Just as the effectiveness of such operations markedly depends on the accuracy with which the position of the probe in the body of the patient is determined, so the quality of the geometric correction of the integral image displayed on monitor 8 lack of visible seams between its fragments) becomes especially significant.

Accordingly, the effectiveness of the operation of geometric distortion corrector 3 depends considerably on the accuracy with which the correction factors Ub(X,y) and are determined in ~,cdigital video signal amplitude corrector 1 3.

However, we know that even when x-ray source 12 is turned off, the video signals Uin(x,y,t) after ADC module 2 are represented by the sum: Uin(x,y,t) Ub(x,y)+Un(x,y,t), (6) where Ub(x,y) is the constant component of the "black" levels (which for different pixels of the image from one of the video cameras 1 and even for different video cameras 1 may have insignificantly different values), and Un(x,y,t) is the fluctuating component, due to noise in said radiation source 12, converter 9, and video cameras 1.

When said source 12 is turned on (during adjustment or when the television system is "idling"), the signal Uin(x,y,t) will be determined by the expression: Uin(x,y,t) Uw(x,y)+Ub(x,y)+Un(x,y,t), (7) where Uw(x,y) is a quantity, essentially constant for a specific video camera, corresponding to the maximum excursion and defined as the product Kw(x,y)*Umax, where Umax is a signal corresponding to the maximum luminance of the image, while Kw(x,y) is the attenuation coefficient (typically less than unity), which is due to the slight nonuniformity in the magnitude of the flux from said source 12, the nonuniformity of converter 9 and the transmission coefficients of the optical systems of video cameras 1, and which is automatically determined and taken into account when the proposed television is started up; Ub(x,y) and Un(x,y,t) are the same as in Using mathematical modeling well known to specialists and/or experimentally, it is not difficult to determine beforehand such averaging coefficients Ak and Bk 1-Ak respectively for the input Uin(x,y) and output Ui(x,y) signals of interframe accumulators 14; when they are used, the effect of said fluctuating components on the quality of the Ui(x,y) signals at the input to video signal amplitude corrector 13 (and later, at the input to geometric distortion corrector 3) will be substantially attenuated.

The codes for said coefficients are fixed .in the memory of the above-mentioned PC 6. During automatic adjustment or when using the proposed television system in most operating modes, these codes for the coefficients Ak and Bk,--according to the control signal from the output of address decoder 67 for the programmable port of PC 6, are sent for writing to input registers 68 of each of the interframe accumulators 14.

Then in the not specially designated recirculator loops of interframe accumulators 14, each of which is assembled on the basis of two multipliers 63 and 64, adder 65, and RAM module 66 (see fig. the input signals Uin(x,y), coming from the corresponding outputs of the above-mentioned ADC module 2, are multiplied by the coefficient Ak and are added to the input signals Ui(x,y) of digital video signal amplitude corrector 13 which have been multiplied by the coefficient Bk, which improves the quality of the synthesized high-resolution images.

In order to control interframe accumulators 14 during adjustment of the proposed video system and especially in the roentgenography operating mode, it is advisable to use multichannel threshold controller 15 (see fig. In fact, each roentgenogram, written to PC 6 in the form of a high-resolution digital video signal, should on reconstruction provide an image quality which will be close to the quality of the images on wide-format x-ray film. At the same time, it is desirable that this quality be achievable in a time no greater than the typical exposure time for roentgenographic procedures.

Of course, minimization of the exposure time (and the ionizing radiation dose absorbed by the patient) cannot always be achieved by just choosing video cameras 1 with suitable sensitivity. Therefore it is desirable, after sufficient averaging of the video signals in interframe accumulators 14, to quickly "freeze" the satisfactory fragments of the integral video output, to record them, and to turn off x-ray source 12.

In order to do this, three thresholds are established beforehand (before the first roentgenography session): the minimal luminance threshold of the fragmentary video signals, which is chosen as a fraction (preferably at least one- Sfourth, but no greater than one-half) of the maximum excursion of ,r 51 the video signals of video cameras 1 used within the television system, and to which the parallel code U1 corresponds; the threshold Ul 1 as the maximum permissible number of pixels in each fragmentary image with luminance less than the specified code UI (it is usually selected within the range 20-35% of the total number of pixels in said image), and the threshold U 12 specifying (usually within the range the number of channels M, out of the total number of channels N, in which the number of pixels with luminance less than the specified code UI is less than the threshold number of pixels UI1.

These thresholds are then used as follows.

When the fragmentary video signals Ucu1(x,y)...UcuN(x,y), corrected in digital amplitude corrector 13, are sent to the first inputs of comparators 69 of. the corresponding channels of multichannel threshold controller 15, then the parallel code of the threshold UI is sent to the second inputs of all these comparators 69 from the above-mentioned PC 6 through input register 76 (RG D).

Then in each channel: the signals at the outputs of comparator 69 and the output of the AND circuit 70 take on the logic level when the following condition is satisfied: Ucui(x,y) UI (8) counter 71 counts the number of pixels of the fragmentary image, for which expression is valid, and accordingly the luminance of which is less than said threshold value, thesequence of pulses Uki at a frequency equal to the frame rate of the television scan and coming from the above-mentioned synchronizer 7, resets counter 71, the pulses counted in the time required for one frame to "pass by" are written in parallel to register 72 at the end of the frame, to the first and second inputs of comparator 73, respectively, are sent: the signal from counter 71 from said register 72, and the threshold code Ui 1 of PC 6 from input register 76.

The logic signal at the output of comparator 73 means that in this channel, the required exposure time is held to.

The logic signals from the outputs of comparators 73 of all the channels, through triggers 74, at the end of the frame of the fragmentary video signal are sent to the inputs of multiplexer 77, i 52 common to all the channels, to the control input of which is sent the X signal from the above-mentioned synchronizer 7.

Counter 79, at a frequency equal to the frame rate of the video cameras 1, counts the number of channels in which the exposure is finished.

Comparator 81, to one of the inputs of which the threshold code U12. is sent through input register 76 from PC 6, generates a logic signal when the exposure is finished in M channels out of N.

The output signal Usr of comparator 81 is sent to the controller of the above-mentioned x-ray source 12 in order to turn it off.

At the end of a frame, the output signal of comparator 81 is rewritten to trigger 82 and is sent to the above-mentioned synchronizer 7, which generates a control signal for switching interframe accumulators 14 to memory mode and generation at their outputs of signals for the "frozen" fragmentary images, which are sent to PC 6 for storage and subsequent reconstruction and analysis of the high-resolution integral image.

For synchronization of the operation of the modules for the proposed television system in its full configuration, synchronizer 7 (see fig. along with the above-mentioned, receives and outputs a series of additional signals, synchronizing the termination of accumulation of an integral number of frames of fragmentary video signals in interframe accumulators 14 with frame sync pulses, and specifically: the D-input of D flip-flop 52 receives the control signal Usn from the output of the above-mentioned multichannel threshold controller a sequence of frame sync pulses from the output of frame pulse selector 38 in synchronizer 7 is sent to the clock C-input of the same D flip-flop 52, along the leading edge of each sync pulse of said sequence, this D flip-flop 52 is set to a logic level corresponding to the control signal Usn, and is reset after each write operation (or on each triggering) according to the commands which come from PC 6 through input register 53 of synchronizer 7 to the R-input of this D flip-flop 52, a signal from the inverted Q\ output of D flip-flop 52 is sent to the first input of AND circuit 51, and a signal fj from the output of the above-mentioned TV sync generator 40 is sent to its second input.

.~-~Kcrr ygi i i 12, DEC. 2001 14:10 WATERMARK 613 9819 6010 NO. 0466 P. 3 53 Thus the control signal Uc is generated, which is a sequence of pulses with signal frequency f, and which provides accumulation of fragmentary video signals in interframe accumulators 14 (for low logic. level of the signal Usn) and acquisition of a "frozen" fragmentary image considerably freed of noise (for high logic level of the signal Usn).

Claims (14)

1. A high-resolution television system having at least two video cameras, analog-to-digital converters (ADCs), a video standards converter, internal memory (RAM), means for synthesizing the video output signal connected to the outputs of the video cameras and interconnected, and a central processor wherein the video output synthesizers include a multichannel geometric distortion corrector and a synchronizer; said corrector is at the same time connected through the ADC to the outputs of the video cameras and through the video standards converter and RAM to the input of the central processor, while the synchronizer is connected through its control input to the synchronization output of at least one of the video cameras, and through its control outputs to the clock input of the ADC, to the address inputs of said corrector and to the address and synchronizing control inputs of the video standards converter. l OQ

2. A television system according to claim 1, including a primary (x-ray) radiation source and a converter of the x-ray image to a visible image which are mounted in series in front of the video cameras. *o

3. A television system according to claim 1, including at least one calibration test object in the form of a three-dimensional target which may be placed in front of the video cameras during adjustment of the system.

4. A television system according to claim 3, including a device for placing the calibration test objects in the field of view and removing them from the field of view from the video cameras, connected to the synchronizing control output of the synchronizer, while this synchronizer is additionally interconnected with the PC by a feedback control loop.

A television system according to any one of the proceeding claims, including a high-resolution monitor, which is connected to the data output of the video image standards converter and RAM. i

6. A television system according to any one of the proceeding claims wherein the multichannel geometric distortion corrector has, in each of the channels: at the input: at least two identical calculation circuits for generating the corrected coordinates along the horizontal and the vertical, respectively, of each of the elements (pixels) of the image in the video output signal, computed on the basis of the initial coordinates of analogous pixels of the image in the input video signal and correction factors; at least two identical slave memory modules for the digital video input signal, connected to said calculation circuits as the sources of the addresses for readout of data on the corrected pixels of the video output signal, while at the output: an inverter, which is inserted between the above-indicated synchronizer and one of said slave memory modules, and an output multiplexer for the alternate connection of the outputs of said slave memory modules to the input of the above-mentioned video standards converters and RAM.

7. A television system according to claim 6, wherein: each of said calculation circuits has at least: one input comparator with fixed threshold digital code, connected to the output of one of the ADCs, one decoder, connected to the address outputs for the pixel coordinates of the input image of the above-mentioned synchronizer, and having two control inputs, two AND logic circuits, each of which is connected to the output of said comparator and to the control output of the synchronizer, and one of which is connected to the first and the other to the second control output of said decoder. two nonvolatile RAMs, in which: the control inputs are independently connected to the outputs of the respective AND logic circuits and k .U 4 address and data inputs are also independently connected respectively to the address inputs of the above-mentioned synchronizer; one decoder, connected to the address output of one of the coordinates of each of the pixels of the input image from the above-mentioned synchronizer (in the process, the signal corresponding to one of the coordinates of each of the pixels of the input image is sent to the data inputs of the first and second nonvolatile RAMs of the first calculation circuit, the signal corresponding to the second coordinate of each of the pixels of the input image arrives at the address inputs of the same RAMs, while said signals are sent in reverse order to the corresponding inputs of the first and second nonvolatile RAMs and to the decoder of the second calculation circuit), one differential stage with two data inputs separately connected respectively to the data outputs of said nonvolatile RAMs, a normalizer for integer division of the digital parallel code of the signal setting one coordinate of each pixel of the distorted image, by the digital S. code of a constant setting one of the geometric dimensions of the undistorted raster (respectively along the horizontal in one calculation circuit and along the vertical in the other calculation circuit). Soo... S. a multiplier for multiplication of the digital codes of one of the S: normalized coordinates of each of the pixels of the input image by the digital code of the active dimension of the distorted raster corresponding to this coordinate, C~O..O an adder for adding the digital codes of the coordinates of the origin of the representation of the distorted raster and the current increment in the S coordinate of the processed pixel of the image in the same raster, while each slave memory module has: two input mulitplexers, each of which is designed for generation of the corresponding digital codes of the coordinates of the pixels of the input and corrected image, and connected to said multiplexers RAM for writing the video input signal to one address and reading the video signal of the corrected image output from the other address.

8. A television system according to any one of the proceeding claims wherein said video standards converter is combined with said RAM and has: -nr r' RAM banks with isolated data inputs, the number of which is equal to the number of video cameras, and to each of which the following are connected: two address multiplexers and two frame buffers; a memory bank control decoder; a first digital-to-analog converter; buffer RAM, containing: memory modules connected in parallel, the number of which is equal to the number of video cameras, and a buffer RAM decoder and a second digital-to-analog converter

9. A television system according to claim 8, wherein *0 a) in each RAM bank: go:t fi- the data inputs of the frame buffers are combined and connected to the corresponding outputs of said multichannel geometric distortion corrector, and 0 Se 0 I0 their data outputs are also combined (including between banks) and connected to the data input of the first digital-to-analog converter; the first inputs of the multiplexers are combined and connected to 0t*9 the synchronizing outputs of the codes for the coordinates for writing the corrected images to the frame buffers in the above-mentioned synchronizer, while the second inputs of the multiplexers are also combined and connected to the synchronizing outputs of the codes for the coordinates for reading the corrected images from the frame buffers in the above-mentioned synchronizer; the first outputs of the first multiplexer are connected to the corresponding address inputs of the first frame buffer, while the first outputs of the second multiplexer are connected to the corresponding address inputs of the second frame buffer; the second control input of the first multiplexer and the second inverted control input of the second multiplexer are connected to the control output of the above-mentioned synchronizer; the first outputs of the multiplexers are connected to the address inputs, their second outputs are connected to the chip-select control inputs, and their third outputs are connected to the read-write control inputs of the corresponding RAMs; b) in all RAM banks: the first control inputs of the first and second multiplexers are combines and connected respectively to the first, second, etc. outputs of the decoder, while the data outputs of all frame buffers are combined and connected to the data input of the first digital-to-analog converter; c) the control input of the decoder is connected to the control output of the above-mentioned synchronizer; d) the first and second control inputs of the first digital-to-analog converter are connected respectively to the synchronizing outputs of the above- mentioned synchronizer, while the data output of this converter is connected to the above-mentioned high-resolution monitor; e) the address inputs of the buffer RAM modules are combined and connected to the synchronizing outputs of the above-mentioned synchronizer with t the codes of the coordinates; their data inputs are connected to the corresponding outputs of the above-mentioned multichannel geometric distortion corrector; their data outputs are combines and connected to the data input of the second digital-to-analog converter; their read-write control inputs are connected 0Se0 to the control output of the above-mentioned synchronizer, while the data input of *0 S: the last said buffer RAM module is connected to the corresponding data input of the frame buffer; f) the control inputs of the buffer RAM decoder are connected to the corresponding control outputs of the above-mentioned synchronizer, while the control outputs of said decoder are connected to the chip-select inputs of the memory modules so that the first of said outputs are connected with said input of the first memory module, the second with the input of the second memory module, etc; g) the data input of the second digital-to-analog converter is connected to the combined data outputs of the memory modules; the control inputs of this converter are connected to, respectively, the synchronizing outputs of said synchronizer, while its data output is connected to the above-mentioned module T for inputting the video signals to the PC. A television system according to any one of the proceeding claims, wherein the synchronizer includes: a first driving generator of synchronizing signals corresponding to the resolution standard of the video cameras, whose clock output is connected to he clock inputs of the above-mentioned ADC modules and of the multichannel threshold controller, and at least one second driving generator of synchronizing signals, corresponding to the high-resolution standard of the synthesized image; two groups of counters respectively for the X and Y coordinates of the pixels of the images formed by each of the video cameras, and two groups of counters respectively for the Xm and Ym coordinates of the pixels of the synthesized high-resolution image; I L. Vzkj. LUU 1 14 -1 U it.

JDU LUU i~.IUYYAIMflVliflt Oh) UOiU OuluPU.U0 .4 11U. U400 r. 4 at least one sync pulse selector to select the original synchronizing pulses from the total television signal and to form output horizontal and vertical synchronizing pulses; two digital comparators respectively for the codes of the Xm and Ym coordinates; two monostable multivibrators for the formation of horizontal -(line) and vertical (frame) pulses corresponding to the high- resolution standard; at least one counter of the number of pixels of the synthesized high-resolution image; an AND circuit for conjunction in the process of formation of control signals for the above-mentioned geometric distortion corrector; an input register for receiving the control commands by said synchronizer, sent from said PC; an output register for sending information about the state of said synchronizer to said PC, and an address decoder for the programmable port. of said PC for outputting the control commands to said synchronizer, in which case: the first driving generator is connected to the count input of the first group of X coordinate counters; the count input of the second group of Y coordinate counters is connected to the output of the horizontal synchronizing pulses of the sync pulse selector; the first group of Xm coordinate counters is connected through the count input to the output of the second driving generator of synchronizing signals; the count input of the second group of Ym coordinate counters is connected to the output of the Xm coordinate counters through one of the digital comparators and one of the monostable multivibrators, connected in series; the reset inputs of the first group of X coordinate counters and of the first group of Xm coordinate counters are connected to the output of the horizontal synchronizing pulses of the sync pulse selector; the reset input of the second group of Y coordinate counters is connected to that output of the sync pulse selector from which the vertical synchronizing pulses corresponding to the full frame of the output image of the video cameras must be taken; IL, ULU. 1UUI 14: U WAIiKMAKR DOlJ U I DUIU U4D0 r. r 61 the reset input of the second group of Ym coordinate counters is connected to that output of the sync pulse selector from which the vertical synchronizing pulses corresponding to the half-frame of the output image of the video cametas must be taken; the output of the first group of Xm coordinate counters is connected: to the inputs of all the multiplexers and to the input of the RAM bank contrdol decoder of the above-mentioned video standards converter with RAM, and through the first digital comparator and the first monostable multivibrator, connected in series, to the digital-to-analog converter of the same converter with RAM, and also to the count input of the second group of Ym coordinate counters; the output of the second group of Ym coordinate counters is connected: to the inputs of all the multiplexers of the above-mentioned video standards converter with RAM, and through the second digital comparator and the second monostable multivibrator, connected in series, to the digital-to- analog converter of the same converter with RAM, and also to the count input of the counter of the number of pixels of the synthesized high-resolution image; the input register is connected: through a parallel data input to the computer, through the first output to the reset input of the counter of the number of pixels of the synthesized high-resolution image and to the control input of the video standards converter with RAM, through the second output to the second input of the AND circuit; through the third output to the reset input of the D flip-flop; the output register is connected: through the first input to the output of the vertical synchronizing pulses of the above-mentioned sync pulse selector, through the second input to the output of the counter of the number of pixels of the synthesized high-resolution image, and through the output to the PC; the address decoder for the programmable port of the PC for outputting control commands to the above-mentioned synchronizer is connected: through the input to the address bus of the PC, and r -through the output to the input of the input register; the counter of the number of pixels of the synthesized high-resolution image is additionally connected to the control input of the buffer RAM decoder of the above-mentioned video standards converter with RAM.

11. A television system according to claim 10, wherein the synchronizer is additionally equipped with a second AND circuit and a D flip-flop; said AND circuit is connected through one input to the output of the driving generator of synchronizing signals corresponding to the resolution standard of the video cameras, through a second input to the inverted output of the D flip-flop, while the output may be used in a supplementary circuit for generation of input signals for the above-mentioned geometric distortion corrector; said D flip-flop is connected: -through the data input to the control output of the above-mentioned multichannel threshold controller, through the synchronizing input to the output of the selector of the sync pulses corresponding to the full frame of the input image, through the reset input to the third output of the above-mentioned input register.

12. A teeiinsystem acrigto claim 2, including a diia video signal amplitude corrector which is connected to the input of the multichannel geometric distortion corrector, with interframe digital video signal accumulators, whose number is usually equal to the number of video cameras and which are inserted between the ADO module and said digital video signal amplitude corrector, and with a multichannel threshold controller, which is connected to the outputs of the digital video signal amplitude corrector, is connected through the above- mentioned synchronizer to the control inputs of the interframe digital video signal accumulators, and is equipped with a feedback control output in a feedback loop with the source of primary (x-ray) radiation. 63

13. A television system according to claim 12, wherein the digital video signal amplitude corrector is multichannel, and has in each channel: two nonvolatile RAMs, which are respectively intended for the storage of the codes of the correction factors of the "black" level and maximum excursion of the video signal for each pixel of the t-l 5,1; j 63a input image from the corresponding (to the given channel) video camera; a differential stage for calculating the difference between the codes of the input signal and the "black" level for each pixel of the input image from the corresponding video camera; a divider for calculating the normalized amplitude correction factors for the video input signals by dividing the con stant. setting the code for the maximum excursion of the video signal for the selected video cameras and AD~s by the varying code corresponding to the maximum excursion of the video signal for each active pixel of the image input from the corresponding video camera; an address decoder for the programmable port of the PC for sending control commands to the given channel of the digital video signal amplitude corrector, in which the input is connected to the address bus of the PC; an input register to receive control commands arriving from PC, in which: -the first input is connected to the PC data bus, the second to the output of the address decoder; -the outputs are connected to the control inputs of the nonvolatile RAMs; videoan output multiplier for generation of codes for the normalized vie output signal by multiplication of the aforementioned normalized factors times the code of the aforementioned difference signal; the first RAM is connected: -through the data input to the output of the corresponding channel of the above-mentioned ADC module, -through the control input to the first output of the input register, the second RAM is connected: through the data input to the output of said differential stage, through the control input to the second output of the input register; both RAMs are connected through the address inputs to the X, Y output of the above-mentioned synchronizer; the differential stage is connected: PW 64 through the first input to the output of the corresponding channel of the above-mentioned ADO module, through the second input to the output of the first RAM, through the output to the first input of said multiplier; the divider is connected between the output of the second RAM and the second input of the multiplier.

14. A television system according to claim 12, wherein the multichannel threshold controller has: in each channel: a first comparator for comparing the codes of the pixels for the image formed by the video camera corresponding to the given channel, with the threshold code, -an AND circuit which throughout the first input is connected to the output O.V. of the comparator and is .designed for strobing the clock signal with the output signal of this comparator, -a counter, the count input of which is connected to the output of said AND circuit, and which serves to calculate the number of such pixels, in the image frame corresponding to the video camera connected to the given channel, whose code exceeds the preset threshold luminance value, -a register, the data input of which is connected to the output of the counter and which serves to store the parallel output code of this counter, -a second comparator whose input is connected through said register to the output of said counter and which serves to compare the output code of this counter with the preset threshold number of pixels of the image that have a luminance no less than the aforementioned threshold value, a trigger, in which the data input is combined with the output of said comparator and which serves for writing the logical output signal of this comparator at the end of the frame synchronization pulse from the above- mentioned synchronizer; and the following, in common for all channels: an address decoder for the programmable port of the PC for outputting to the multichannel threshold controller the codes of the luminance threshold values, of the number of pixels with a luminance no less than the threshold value, and of S Xr?~V~A~ the number of channels with logic level at the outputs, in which the input is connected to the address bus of the PC, an input register for receiving the codes of said threshold values arriving from the PC, in which the first (data) input is connected to the PC data bus, while the second (clock) input is connected to the output of the address decoder, the first output (of the code of the luminance threshold value) is connected to the combined first inputs of the first comparators of all channels, while the second output (the code of the number of pixels with a luminance no less than the preset value) is connected to the combines second inputs of the second comparators of all the channels, a multiplexer for multiplexing the output signals of all the channels, in which are each of the data inputs is connected to the outputs of the triggers of the corresponding channels, while the control input is connected to the synchronizing output of the above-mentioned synchronizer with the X coordinate code; -an AND circuit for strobing the clock signal with the output signal of said multiplexer, in which the first input is connected to the output of the multiplexer, while the second input is connected to the combined second inputs of said AND circuits of each of the channels of the multichannel threshold controller and is connected to the clock output of the above-mentioned synchronizer; -a counter for counting of the number of those channels whose signals at .the outputs of the triggers have logic level and which is connected though the count input to the output of said AND circuit, while it is connected throughout the reset input across the inverter to the frame synchronization pulse output of the above-mentioned synchronizer; a comaparator for comparing the output code of the counter with the threshold value of the number of channels with logic level at the outputs, connected through the first and second data inputs respectively to the output of the counter and to the third output of said input register, while it is connected through the output to the controller of the primary (x-ray) radiation source, a trigger for writing and storing the outputs signal of said comparator, connected throughout the data input to the output of said comparator, throughout the clock input across said inverter to the frame synchronization pulse output of the above-mentioned synchronizer, and connected through the control output to rssv<tyrs~n~ ~Vt~tWr-f-tZ~. 66 the above-mentioned interframe accumulators across the above-mentioned synchronizer; in which case: in each of the channels, the following are combined and jointly connected to the frame synchronization pulse output of the above-mentions synchronizer: the reset inputs of the counters of the number of pixels with a luminance no less than the preset value, the clock inputs of all registers and the clock inputs of all triggers, while the second inputs of the first comparators of all channels are connected to the corresponding data outputs of the above-mentions digital video signal amplitude corrector. A high-resolution television system according to claim 1 substantially as hereinbefore described with reference tot he accompanying drawings. SERGY IVANOVICH MIROSHNICHENKO *HAWTHORN VICTORIA 3122 AUSTRALIA RCS/NWM/GLM °o